Added nullability to Printing and tests

Core/Collections/VirtualList.cs

@@ -0,0 +1,234 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Vanara.Collections;
+
+/// <summary>Interface that defines the methods for a virtual list. This interface is used by the <see cref="VirtualList{T}"/> class.</summary>
+/// <typeparam name="T">The type of the element.</typeparam>
+/// <seealso cref="IVirtualReadOnlyListMethods&lt;T&gt;"/>
+public interface IVirtualListMethods<T> : IVirtualReadOnlyListMethods<T>
+{
+	/// <summary>Adds an item to the end of the list.</summary>
+	/// <param name="item">The object to add to the list.</param>
+	void AddItem(T item);
+
+	/// <summary>Inserts an item to the list at the specified index.</summary>
+	/// <param name="index">The zero-based index at which item should be inserted.</param>
+	/// <param name="item">The object to insert into the list.</param>
+	void InsertItemAt(int index, T item);
+
+	/// <summary>Removes the item at the specified index.</summary>
+	/// <param name="index">The zero-based index of the item to remove.</param>
+	void RemoveItemAt(int index);
+
+	/// <summary>Sets the element at the specified index.</summary>
+	/// <param name="index">The zero-based index of the element to set.</param>
+	/// <param name="value">The element at the specified index.</param>
+	void SetItemAt(int index, T value);
+}
+
+/// <summary>
+/// Interface that defines the methods for a virtual read-only list. This interface is used by the <see cref="VirtualReadOnlyList{T}"/> class.
+/// </summary>
+/// <typeparam name="T">The type of the element.</typeparam>
+public interface IVirtualReadOnlyListMethods<T>
+{
+	/// <summary>Gets the number of elements in the collection.</summary>
+	/// <returns>The number of elements in the collection.</returns>
+	int GetItemCount();
+
+	/// <summary>Tries to get the element at the specified index.</summary>
+	/// <param name="index">The zero-based index of the element to get.</param>
+	/// <param name="value">The value, if <paramref name="index"/> is a valid index; or <see langword="default"/> if not.</param>
+	/// <returns><see langword="true"/> if the list contains an element at the specified index; otherwise, <see langword="false"/>.</returns>
+	bool TryGet(int index, [NotNullWhen(true)] out T? value);
+}
+
+/// <summary>A virtual list that implements a lot of the scaffolding.</summary>
+/// <typeparam name="T">The element type.</typeparam>
+public class VirtualList<T> : VirtualReadOnlyList<T>, IList<T>
+{
+	/// <summary>The implementation.</summary>
+	protected readonly IVirtualListMethods<T> impl;
+
+	/// <summary>Initializes a new instance of the <see cref="VirtualList{T}"/> class.</summary>
+	public VirtualList(IVirtualListMethods<T> impl) : base(impl) => this.impl = impl;
+
+	/// <inheritdoc/>
+	bool ICollection<T>.IsReadOnly => false;
+
+	/// <inheritdoc/>
+	public new T this[int index]
+	{
+		get => base[index];
+		set => impl.SetItemAt(index, value);
+	}
+
+	/// <inheritdoc/>
+	public void Add(T item) => impl.AddItem(item);
+
+	/// <inheritdoc/>
+	public void Clear()
+	{
+		for (int i = Count - 1; i >= 0; i--)
+			RemoveAt(i);
+	}
+
+	/// <inheritdoc/>
+	public void Insert(int index, T item) => impl.InsertItemAt(index, item);
+
+	/// <inheritdoc/>
+	public bool Remove(T item)
+	{
+		int i = IndexOf(item);
+		if (i >= 0)
+		{
+			RemoveAt(i);
+			return true;
+		}
+		return false;
+	}
+
+	/// <inheritdoc/>
+	public void RemoveAt(int index) => impl.RemoveItemAt(index);
+
+	/// <inheritdoc/>
+	IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+}
+
+/// <summary>Wrapper for <see cref="IVirtualListMethods{T}"/> that allows for the use of delegates instead of implementing the interface.</summary>
+/// <typeparam name="T">The element type.</typeparam>
+/// <seealso cref="IVirtualListMethods&lt;T&gt;"/>
+public class VirtualListMethodCarrier<T> : IVirtualListMethods<T>
+{
+	/// <summary>Initializes a new instance of the <see cref="VirtualListMethodCarrier{T}"/> class.</summary>
+	/// <param name="tryGet">Delegate that tries to get the element at the specified index.</param>
+	/// <param name="getCount">Delegate that gets the number of elements in the collection.</param>
+	/// <param name="add">Delegate that adds an item to the end of the list.</param>
+	/// <param name="insert">Delegate that inserts an item to the list at the specified index.</param>
+	/// <param name="removeAt">Delegate that removes the item at the specified index.</param>
+	/// <param name="setAt">Delegate that sets the element at the specified index.</param>
+	public VirtualListMethodCarrier(VirtualReadOnlyList<T>.TryGetDelegate tryGet, Func<int> getCount, Action<T>? add = null, Action<int, T>? insert = null, Action<int>? removeAt = null, Action<int, T>? setAt = null)
+	{
+		TryGet = tryGet;
+		GetCount = getCount;
+		Add = add;
+		Insert = insert;
+		RemoveAt = removeAt;
+		SetAt = setAt;
+	}
+
+	/// <summary>Delegate that adds an item to the end of the list.</summary>
+	public Action<T>? Add { get; }
+
+	/// <summary>Delegate that gets the number of elements in the collection.</summary>
+	public Func<int> GetCount { get; }
+
+	/// <summary>Delegate that inserts an item to the list at the specified index.</summary>
+	public Action<int, T>? Insert { get; }
+
+	/// <summary>Delegate that removes the item at the specified index.</summary>
+	public Action<int>? RemoveAt { get; }
+
+	/// <summary>Delegate that sets the element at the specified index.</summary>
+	public Action<int, T>? SetAt { get; }
+
+	/// <summary>Delegate that tries to get the element at the specified index.</summary>
+	public VirtualReadOnlyList<T>.TryGetDelegate TryGet { get; }
+
+	/// <inheritdoc/>
+	void IVirtualListMethods<T>.AddItem(T item) => Add?.Invoke(item);
+
+	/// <inheritdoc/>
+	int IVirtualReadOnlyListMethods<T>.GetItemCount() => GetCount();
+
+	/// <inheritdoc/>
+	void IVirtualListMethods<T>.InsertItemAt(int index, T item) => Insert?.Invoke(index, item);
+
+	/// <inheritdoc/>
+	void IVirtualListMethods<T>.RemoveItemAt(int index) => RemoveAt?.Invoke(index);
+
+	/// <inheritdoc/>
+	void IVirtualListMethods<T>.SetItemAt(int index, T value) => SetAt?.Invoke(index, value);
+
+	/// <inheritdoc/>
+	bool IVirtualReadOnlyListMethods<T>.TryGet(int index, [NotNullWhen(true)] out T? value) => TryGet(index, out value);
+}
+
+/// <summary>A virtual read-only list that implements a lot of the scaffolding.</summary>
+/// <typeparam name="T">The element type.</typeparam>
+public class VirtualReadOnlyList<T> : IReadOnlyList<T>
+{
+	/// <summary>The read only implementation.</summary>
+	protected readonly IVirtualReadOnlyListMethods<T> readOnlyImpl;
+
+	/// <summary>Initializes a new instance of the <see cref="VirtualList{T}"/> class.</summary>
+	public VirtualReadOnlyList(IVirtualReadOnlyListMethods<T> impl) => readOnlyImpl = impl;
+
+	/// <summary>Delegate for a method that tries to get the element at the specified index.</summary>
+	/// <param name="index">The zero-based index of the element to get.</param>
+	/// <param name="value">The value, if <paramref name="index"/> is a valid index; or <see langword="default"/> if not.</param>
+	/// <returns><see langword="true"/> if the list contains an element at the specified index; otherwise, <see langword="false"/>.</returns>
+	public delegate bool TryGetDelegate(int index, [NotNullWhen(true)] out T? value);
+
+	/// <inheritdoc/>
+	public virtual int Count => readOnlyImpl.GetItemCount();
+
+	/// <inheritdoc/>
+	public virtual T this[int index] => readOnlyImpl.TryGet(index, out T? v) ? v : throw new ArgumentOutOfRangeException(nameof(index));
+
+	/// <inheritdoc/>
+	public virtual bool Contains(T item) => IndexOf(item) >= 0;
+
+	/// <inheritdoc/>
+	public virtual void CopyTo(T[] array, int arrayIndex)
+	{
+		if (array is null)
+			throw new ArgumentNullException(nameof(array));
+		if (arrayIndex < 0 || arrayIndex > array.Length)
+			throw new ArgumentOutOfRangeException(nameof(arrayIndex));
+		if (array.Length - arrayIndex < Count)
+			throw new ArgumentException("The number of elements in the source ICollection<T> is greater than the available space from arrayIndex to the end of the destination array.");
+
+		for (int i = 0; i < Count; i++)
+			array[arrayIndex + i] = this[i];
+	}
+
+	/// <inheritdoc/>
+	public virtual IEnumerator<T> GetEnumerator()
+	{
+		for (int i = 0; i < Count; i++)
+			yield return this[i];
+	}
+
+	/// <inheritdoc/>
+	public virtual int IndexOf(T item)
+	{
+		for (int i = 0; i < Count; i++)
+		{
+			/* Unmerged change from project 'Vanara.PInvoke.Printing (net48)'
+			Before:
+							if (Equals(this[i], item))
+			After:
+					{
+						if (Equals(this[i], item))
+			*/
+			if (Equals(this[i], item))
+				return i;
+		}
+
+		/* Unmerged change from project 'Vanara.PInvoke.Printing (net48)'
+		Before:
+					return -1;
+		After:
+				}
+
+				return -1;
+		*/
+		return -1;
+	}
+
+	/// <inheritdoc/>
+	IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+}

PInvoke/Opc/MsOpc.cs

@@ -6833,9 +6833,8 @@ public static partial class Opc
 		public OpcEnumerator(TEnum opcEnumerator)
 		{
 			opcEnum = opcEnumerator ?? throw new ArgumentNullException(nameof(opcEnumerator));
-			moveNext = typeof(TEnum).GetMethod("MoveNext");
-			getCurrent = typeof(TEnum).GetMethod("GetCurrent");
-			if (moveNext is null || getCurrent is null) throw new ArgumentException("The type specified for TEnum is not a valid Opc Enumerator instance.");
+			moveNext = typeof(TEnum).GetMethod("MoveNext") ?? throw new ArgumentException("Unable to find MoveNext method in TEnum type.", nameof(TEnum));
+			getCurrent = typeof(TEnum).GetMethod("GetCurrent") ?? throw new ArgumentException("Unable to find GetCurrent method in TEnum type.", nameof(TEnum));
 		}
 
 		/// <summary>Gets the element in the collection at the current position of the enumerator.</summary>
@@ -6844,7 +6843,7 @@ public static partial class Opc
 			get
 			{
 				var p = new object?[] { null };
-				((HRESULT)getCurrent.Invoke(opcEnum, p)).ThrowIfFailed();
+				((HRESULT)getCurrent.Invoke(opcEnum, p)!).ThrowIfFailed();
 				return (TElem)p[0]!;
 			}
 		}
@@ -6863,7 +6862,7 @@ public static partial class Opc
 		public bool MoveNext()
 		{
 			var p = new object[] { false };
-			((HRESULT)moveNext.Invoke(opcEnum, p)).ThrowIfFailed();
+			((HRESULT)moveNext.Invoke(opcEnum, p)!).ThrowIfFailed();
 			return (bool)p[0];
 		}
 

PInvoke/PhotoAcquire/PhotoAcquire.cs

@@ -1,4 +1,3 @@
-#nullable enable
 using System.Runtime.InteropServices.ComTypes;
 using static Vanara.PInvoke.Gdi32;
 using static Vanara.PInvoke.Ole32;
@@ -11,6 +10,7 @@ namespace Vanara.PInvoke;
 /// <summary>Enums and interfaces from the Windows Photo Acquisition API.</summary>
 public static partial class PhotoAcquisition
 {
+#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
 	public static readonly HRESULT PAQ_ERR = HRESULT.Make(true, HRESULT.FacilityCode.FACILITY_ITF, 0xA001);
 	public static readonly PROPERTYKEY PKEY_PhotoAcquire_CameraSequenceNumber = new(new(0x00f23377, 0x7ac6, 0x4b7a, 0x84, 0x43, 0x34, 0x5e, 0x73, 0x1f, 0xa5, 0x7a), 7);    // VT_LPWSTR
 	public static readonly PROPERTYKEY PKEY_PhotoAcquire_DuplicateDetectionID = new(new(0x00f23377, 0x7ac6, 0x4b7a, 0x84, 0x43, 0x34, 0x5e, 0x73, 0x1f, 0xa5, 0x7a), 10);    // VT_I4
@@ -21,6 +21,7 @@ public static partial class PhotoAcquisition
 	public static readonly PROPERTYKEY PKEY_PhotoAcquire_RelativePathname = new(new(0x00f23377, 0x7ac6, 0x4b7a, 0x84, 0x43, 0x34, 0x5e, 0x73, 0x1f, 0xa5, 0x7a), 2); // VT_LPWSTR
 	public static readonly PROPERTYKEY PKEY_PhotoAcquire_SkipImport = new(new(0x00f23377, 0x7ac6, 0x4b7a, 0x84, 0x43, 0x34, 0x5e, 0x73, 0x1f, 0xa5, 0x7a), 9);    // VT_BOOL
 	public static readonly PROPERTYKEY PKEY_PhotoAcquire_TransferResult = new(new(0x00f23377, 0x7ac6, 0x4b7a, 0x84, 0x43, 0x34, 0x5e, 0x73, 0x1f, 0xa5, 0x7a), 5);    // VT_SCODE
+#pragma warning restore CS1591 // Missing XML comment for publicly visible type or member
 
 	/// <summary>The enumeration type indicates the type of a selected device.</summary>
 	/// <remarks>This enumeration type is pointed to by the <c>pnDeviceType</c> parameter of IPhotoAcquireDeviceSelectionDialog::DoModal.</remarks>
@@ -453,8 +454,8 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquire-acquire HRESULT Acquire( [in]
 		// IPhotoAcquireSource *pPhotoAcquireSource, [in] BOOL fShowProgress, [in] HWND hWndParent, [in] LPCWSTR pszApplicationName, [in]
 		// IPhotoAcquireProgressCB *pPhotoAcquireProgressCB );
-		void Acquire([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource pPhotoAcquireSource, [In, MarshalAs(UnmanagedType.Bool)] bool fShowProgress,
-			[In, Optional] HWND hWndParent, [In, Optional, MarshalAs(UnmanagedType.LPWStr)] string? pszApplicationName, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireProgressCB pPhotoAcquireProgressCB);
+		void Acquire([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource? pPhotoAcquireSource, [In, MarshalAs(UnmanagedType.Bool)] bool fShowProgress,
+			[In, Optional] HWND hWndParent, [In, Optional, MarshalAs(UnmanagedType.LPWStr)] string? pszApplicationName, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireProgressCB? pPhotoAcquireProgressCB);
 
 		/// <summary>
 		/// The method retrieves an enumeration containing the paths of all files successfully transferred during the most recent call to Acquire.
@@ -747,7 +748,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireplugin-initialize HRESULT
 		// Initialize( [in] IPhotoAcquireSource *pPhotoAcquireSource, [in] IPhotoAcquireProgressCB *pPhotoAcquireProgressCB );
 		[PreserveSig]
-		HRESULT Initialize([In, Optional] IPhotoAcquireSource pPhotoAcquireSource, [In, Optional] IPhotoAcquireProgressCB pPhotoAcquireProgressCB);
+		HRESULT Initialize([In, Optional] IPhotoAcquireSource? pPhotoAcquireSource, [In, Optional] IPhotoAcquireProgressCB? pPhotoAcquireProgressCB);
 
 		/// <summary>
 		/// The method provides additional functionality each time an item is processed. The application provides the implementation of the method.
@@ -806,8 +807,8 @@ public static partial class PhotoAcquisition
 		// ProcessItem( [in] DWORD dwAcquireStage, [in] IPhotoAcquireItem *pPhotoAcquireItem, [in] IStream *pOriginalItemStream, [in] LPCWSTR
 		// pszFinalFilename, [in] IPropertyStore *pPropertyStore );
 		[PreserveSig]
-		HRESULT ProcessItem(PAPS dwAcquireStage, [In, Optional] IPhotoAcquireItem pPhotoAcquireItem, [In, Optional] IStream pOriginalItemStream,
-			string pszFinalFilename, [In, Optional] IPropertyStore pPropertyStore);
+		HRESULT ProcessItem(PAPS dwAcquireStage, [In, Optional] IPhotoAcquireItem? pPhotoAcquireItem, [In, Optional] IStream? pOriginalItemStream,
+			string? pszFinalFilename, [In, Optional] IPropertyStore? pPropertyStore);
 
 		/// <summary>
 		/// Provides extended functionality when a transfer session is completed. The application provides the implementation of the
@@ -928,7 +929,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireprogresscb-startenumeration HRESULT
 		// StartEnumeration( [in] IPhotoAcquireSource *pPhotoAcquireSource );
 		[PreserveSig]
-		HRESULT StartEnumeration([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource pPhotoAcquireSource);
+		HRESULT StartEnumeration([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource? pPhotoAcquireSource);
 
 		/// <summary>
 		/// The method provides extended functionality each time an item is found during enumeration of items from the device. This method
@@ -1023,7 +1024,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireprogresscb-starttransfer HRESULT
 		// StartTransfer( [in] IPhotoAcquireSource *pPhotoAcquireSource );
 		[PreserveSig]
-		HRESULT StartTransfer([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource pPhotoAcquireSource);
+		HRESULT StartTransfer([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource? pPhotoAcquireSource);
 
 		/// <summary>
 		/// The method provides extended functionality each time the transfer of an item begins. The application provides the implementation
@@ -1054,7 +1055,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireprogresscb-startitemtransfer HRESULT
 		// StartItemTransfer( [in] UINT nItemIndex, [in] IPhotoAcquireItem *pPhotoAcquireItem );
 		[PreserveSig]
-		HRESULT StartItemTransfer([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem pPhotoAcquireItem);
+		HRESULT StartItemTransfer([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem? pPhotoAcquireItem);
 
 		/// <summary>
 		/// The method provides extended functionality when a destination directory is created during the acquisition process. The
@@ -1150,7 +1151,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireprogresscb-enditemtransfer HRESULT
 		// EndItemTransfer( [in] UINT nItemIndex, [in] IPhotoAcquireItem *pPhotoAcquireItem, [in] HRESULT hr );
 		[PreserveSig]
-		HRESULT EndItemTransfer([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem pPhotoAcquireItem, HRESULT hr);
+		HRESULT EndItemTransfer([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem? pPhotoAcquireItem, HRESULT hr);
 
 		/// <summary>
 		/// The method provides extended functionality when the transfer of all files is complete. The application provides the
@@ -1210,7 +1211,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireprogresscb-startdelete HRESULT
 		// StartDelete( [in] IPhotoAcquireSource *pPhotoAcquireSource );
 		[PreserveSig]
-		HRESULT StartDelete([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource pPhotoAcquireSource);
+		HRESULT StartDelete([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireSource? pPhotoAcquireSource);
 
 		/// <summary>
 		/// The method provides extended functionality each time the deletion of an individual item from the device begins. The application
@@ -1241,7 +1242,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireprogresscb-startitemdelete HRESULT
 		// StartItemDelete( [in] UINT nItemIndex, [in] IPhotoAcquireItem *pPhotoAcquireItem );
 		[PreserveSig]
-		HRESULT StartItemDelete([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem pPhotoAcquireItem);
+		HRESULT StartItemDelete([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem? pPhotoAcquireItem);
 
 		/// <summary>
 		/// The method provides extended functionality when the percentage of items deleted changes. The application provides the
@@ -1303,7 +1304,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquireprogresscb-enditemdelete HRESULT
 		// EndItemDelete( [in] UINT nItemIndex, [in] IPhotoAcquireItem *pPhotoAcquireItem, [in] HRESULT hr );
 		[PreserveSig]
-		HRESULT EndItemDelete([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem pPhotoAcquireItem, HRESULT hr);
+		HRESULT EndItemDelete([In] uint nItemIndex, [In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireItem? pPhotoAcquireItem, HRESULT hr);
 
 		/// <summary>
 		/// The method provides extended functionality when deletion of files from the image source is complete. The application provides the
@@ -1561,8 +1562,8 @@ public static partial class PhotoAcquisition
 		// GetUserInput( [in] REFIID riidType, [in] IUnknown *pUnknown, [out] PROPVARIANT *pPropVarResult, [in] const PROPVARIANT
 		// *pPropVarDefault );
 		[PreserveSig]
-		HRESULT GetUserInput(in Guid riidType, [In, Optional, MarshalAs(UnmanagedType.IUnknown, IidParameterIndex = 0)] object pUnknown,
-			[Out] PROPVARIANT pPropVarResult, [In, Optional] PROPVARIANT pPropVarDefault);
+		HRESULT GetUserInput(in Guid riidType, [In, Optional, MarshalAs(UnmanagedType.IUnknown, IidParameterIndex = 0)] object? pUnknown,
+			[Out] PROPVARIANT pPropVarResult, [In, Optional] PROPVARIANT? pPropVarDefault);
 	}
 
 	/// <summary>The interface is used to work with image acquisition settings, such as file name format.</summary>
@@ -1783,7 +1784,7 @@ public static partial class PhotoAcquisition
 		// https://learn.microsoft.com/en-us/windows/win32/api/photoacquire/nf-photoacquire-iphotoacquiresource-initializeitemlist HRESULT
 		// InitializeItemList( [in] BOOL fForceEnumeration, [in] IPhotoAcquireProgressCB *pPhotoAcquireProgressCB, [out] UINT *pnItemCount );
 		void InitializeItemList([In, MarshalAs(UnmanagedType.Bool)] bool fForceEnumeration,
-			[In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireProgressCB pPhotoAcquireProgressCB, out uint pnItemCount);
+			[In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoAcquireProgressCB? pPhotoAcquireProgressCB, out uint pnItemCount);
 
 		/// <summary>The method retrieves the number of items found by the InitializeItemList method.</summary>
 		/// <returns>Pointer to an integer value containing the item count.</returns>
@@ -1976,7 +1977,7 @@ public static partial class PhotoAcquisition
 		/// <param name="pPhotoProgressActionCB">
 		/// A reference to a <see cref="IPhotoProgressActionCB"/> derived class that responds to the action link click.
 		/// </param>
-		void SetActionLinkCallback([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoProgressActionCB pPhotoProgressActionCB);
+		void SetActionLinkCallback([In, Optional, MarshalAs(UnmanagedType.Interface)] IPhotoProgressActionCB? pPhotoProgressActionCB);
 
 		/// <summary>The method sets the text for the action link in the progress dialog box.</summary>
 		/// <param name="pszCaption">A string containing the action link text.</param>
@@ -2007,8 +2008,8 @@ public static partial class PhotoAcquisition
 		// GetUserInput( [in] REFIID riidType, [in] IUnknown *pUnknown, [out] PROPVARIANT *pPropVarResult, [in] const PROPVARIANT
 		// *pPropVarDefault );
 		[PreserveSig]
-		HRESULT GetUserInput(in Guid riidType, [In, Optional, MarshalAs(UnmanagedType.IUnknown, IidParameterIndex = 0)] object pUnknown,
-			[Out] PROPVARIANT pPropVarResult, [In, Optional] PROPVARIANT pPropVarDefault);
+		HRESULT GetUserInput(in Guid riidType, [In, Optional, MarshalAs(UnmanagedType.IUnknown, IidParameterIndex = 0)] object? pUnknown,
+			[Out] PROPVARIANT pPropVarResult, [In, Optional] PROPVARIANT? pPropVarDefault);
 	}
 
 	/// <summary>Retrieves descriptive information entered by the user, such as the tag name of the images to store.</summary>
@@ -2026,7 +2027,7 @@ public static partial class PhotoAcquisition
 	// GetUserInput( [in] REFIID riidType, [in] IUnknown *pUnknown, [out] PROPVARIANT *pPropVarResult, [in] const PROPVARIANT
 	// *pPropVarDefault );
 	[PreserveSig]
-	public static string? GetUserInput(this IPhotoProgressDialog dlg, [In, Optional] IUserInputString pUnknown, [In, Optional] string? pPropVarDefault)
+	public static string? GetUserInput(this IPhotoProgressDialog dlg, [In, Optional] IUserInputString? pUnknown, [In, Optional] string? pPropVarDefault)
 	{
 		if (dlg == null) throw new ArgumentNullException(nameof(dlg));
 		using PROPVARIANT res = new();

PInvoke/Printing/PrntvPt.cs

@@ -134,7 +134,7 @@ public static partial class PrntvPt
 	[PInvokeData("prntvpt.h", MSDNShortId = "3b0a6afd-fa9d-434e-a95f-b051296d4567")]
 	public static extern HRESULT ConvertPrintTicketToDevModeThunk2(HPTPROVIDER hProvider, [In] IntPtr pPrintTicket, uint cbSize,
 		EDefaultDevmodeType baseType, EPrintTicketScope scope, out SafeCoTaskMemHandle ppDevmode, out uint pcbDevModeLength,
-		[MarshalAs(UnmanagedType.BStr)] out string errMsg);
+		[MarshalAs(UnmanagedType.BStr)] out string? errMsg);
 
 	/// <summary>
 	/// <para>
@@ -168,7 +168,7 @@ public static partial class PrntvPt
 	[DllImport(Lib.PrntvPt, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("winspool.h", MSDNShortId = "15219c19-b64c-4c51-9357-15a797557693")]
 	public static extern HRESULT GetPrintCapabilitiesThunk2(HPTPROVIDER hProvider, [In] IntPtr pPrintTicket, int cbPrintTicket, out IntPtr ppbPrintCapabilities,
-		out int pcbPrintCapabilitiesLength, [MarshalAs(UnmanagedType.BStr)] out string pbstrErrorMessage);
+		out int pcbPrintCapabilitiesLength, [MarshalAs(UnmanagedType.BStr)] out string? pbstrErrorMessage);
 
 	/// <summary>
 	/// <para>
@@ -215,8 +215,8 @@ public static partial class PrntvPt
 	[DllImport(Lib.PrntvPt, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("prntvpt.h", MSDNShortId = "4aa7b9de-abf2-4781-942e-0b992a6bffed")]
 	public static extern HRESULT MergeAndValidatePrintTicketThunk2(HPTPROVIDER hProvider, [In] IntPtr pBasePrintTicket, int basePrintTicketLength,
-		[In] IntPtr pDeltaPrintTicket, int deltaPrintTicketLength, EPrintTicketScope scope, out SafeCoTaskMemHandle ppValidatedPrintTicket,
-		out int pValidatedPrintTicketLength, [MarshalAs(UnmanagedType.BStr)] out string pbstrErrorMessage);
+		[In, Optional] IntPtr pDeltaPrintTicket, int deltaPrintTicketLength, EPrintTicketScope scope, out SafeCoTaskMemHandle ppValidatedPrintTicket,
+		out int pValidatedPrintTicketLength, [MarshalAs(UnmanagedType.BStr)] out string? pbstrErrorMessage);
 
 	/// <summary>Closes a print ticket provider handle.</summary>
 	/// <param name="hProvider">A handle to the provider. This handle is returned by the PTOpenProvider or PTOpenProviderEx function.</param>
@@ -344,7 +344,7 @@ public static partial class PrntvPt
 	[DllImport(Lib.PrntvPt, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("prntvpt.h", MSDNShortId = "5eec91b9-d554-4440-bc9e-6a26af34994b")]
 	public static extern HRESULT PTConvertPrintTicketToDevMode(HPTPROVIDER hProvider, IStream pPrintTicket, EDefaultDevmodeType baseDevmodeType,
-		EPrintTicketScope scope, out uint pcbDevmode, out SafePTMemory ppDevmode, [MarshalAs(UnmanagedType.BStr)] out string pbstrErrorMessage);
+		EPrintTicketScope scope, out uint pcbDevmode, out SafePTMemory ppDevmode, [MarshalAs(UnmanagedType.BStr)] out string? pbstrErrorMessage);
 
 	/// <summary>Retrieves the printer's capabilities formatted in compliance with the XML Print Schema.</summary>
 	/// <param name="hProvider">
@@ -393,8 +393,8 @@ public static partial class PrntvPt
 	// HPTPROVIDER hProvider, IStream *pPrintTicket, IStream *pCapabilities, BSTR *pbstrErrorMessage );
 	[DllImport(Lib.PrntvPt, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("prntvpt.h", MSDNShortId = "925e314c-85ff-4c1b-b3c9-f36aa4b55e01")]
-	public static extern HRESULT PTGetPrintCapabilities(HPTPROVIDER hProvider, [Optional] IStream pPrintTicket, IStream pCapabilities,
-		[MarshalAs(UnmanagedType.BStr)] out string pbstrErrorMessage);
+	public static extern HRESULT PTGetPrintCapabilities(HPTPROVIDER hProvider, [Optional] IStream? pPrintTicket, IStream pCapabilities,
+		[MarshalAs(UnmanagedType.BStr)] out string? pbstrErrorMessage);
 
 	/// <summary>Retrieves the device printer's capabilities formatted in compliance with the XML Print Schema.</summary>
 	/// <param name="hProvider">
@@ -416,8 +416,8 @@ public static partial class PrntvPt
 	// PTGetPrintDeviceCapabilities( HPTPROVIDER hProvider, IStream *pPrintTicket, IStream *pDeviceCapabilities, BSTR *pbstrErrorMessage );
 	[DllImport(Lib.PrntvPt, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("prntvpt.h", MSDNShortId = "DB9D63B1-2703-47F7-8F31-30FA0110E1E9")]
-	public static extern HRESULT PTGetPrintDeviceCapabilities(HPTPROVIDER hProvider, [Optional] IStream pPrintTicket, IStream pDeviceCapabilities,
-		[MarshalAs(UnmanagedType.BStr)] out string pbstrErrorMessage);
+	public static extern HRESULT PTGetPrintDeviceCapabilities(HPTPROVIDER hProvider, [Optional] IStream? pPrintTicket, IStream pDeviceCapabilities,
+		[MarshalAs(UnmanagedType.BStr)] out string? pbstrErrorMessage);
 
 	/// <summary>It retrieves the print devices resources for a printer formatted in compliance with the XML Print Schema.</summary>
 	/// <param name="hProvider">
@@ -440,8 +440,8 @@ public static partial class PrntvPt
 	// *pbstrErrorMessage );
 	[DllImport(Lib.PrntvPt, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("prntvpt.h", MSDNShortId = "39F17562-B8EB-41AF-BA55-42FE35B4560F")]
-	public static extern HRESULT PTGetPrintDeviceResources(HPTPROVIDER hProvider, [MarshalAs(UnmanagedType.LPWStr)] string pszLocaleName,
-		[Optional] IStream pPrintTicket, IStream pDeviceResources, [MarshalAs(UnmanagedType.BStr)] out string pbstrErrorMessage);
+	public static extern HRESULT PTGetPrintDeviceResources(HPTPROVIDER hProvider, [MarshalAs(UnmanagedType.LPWStr)] string? pszLocaleName,
+		[Optional] IStream? pPrintTicket, IStream pDeviceResources, [MarshalAs(UnmanagedType.BStr)] out string? pbstrErrorMessage);
 
 	/// <summary>Merges two print tickets and returns a valid, viable print ticket.</summary>
 	/// <param name="hProvider">
@@ -530,8 +530,8 @@ public static partial class PrntvPt
 	// IStream *pResultTicket, BSTR *pbstrErrorMessage );
 	[DllImport(Lib.PrntvPt, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("prntvpt.h", MSDNShortId = "97691930-d76a-48c9-80b9-8413d96322a9")]
-	public static extern HRESULT PTMergeAndValidatePrintTicket(HPTPROVIDER hProvider, IStream pBaseTicket, [Optional] IStream pDeltaTicket,
-		EPrintTicketScope scope, IStream pResultTicket, [MarshalAs(UnmanagedType.BStr)] out string pbstrErrorMessage);
+	public static extern HRESULT PTMergeAndValidatePrintTicket(HPTPROVIDER hProvider, IStream pBaseTicket, [Optional] IStream? pDeltaTicket,
+		EPrintTicketScope scope, IStream pResultTicket, [MarshalAs(UnmanagedType.BStr)] out string? pbstrErrorMessage);
 
 	/// <summary>Opens an instance of a print ticket provider.</summary>
 	/// <param name="pszPrinterName">A pointer to the full name of a print queue.</param>
@@ -694,7 +694,7 @@ public static partial class PrntvPt
 		public static bool operator ==(HPTPROVIDER h1, HPTPROVIDER h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object? obj) => obj is HPTPROVIDER h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HPTPROVIDER h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();
@@ -741,7 +741,7 @@ public static partial class PrntvPt
 		/// <summary>Converts the memory held by this object to a structure.</summary>
 		/// <typeparam name="T">The type of the structure.</typeparam>
 		/// <returns>A structure marshaled from this memory.</returns>
-		public T ToStructure<T>() => IsInvalid ? default : handle.ToStructure<T>();
+		public T? ToStructure<T>() => IsInvalid ? default : handle.ToStructure<T>();
 
 		/// <inheritdoc/>
 		protected override bool InternalReleaseHandle() => PTReleaseMemory(handle).Succeeded;

PInvoke/Printing/WinSpool.DrvFuncs.cs

@@ -950,11 +950,11 @@ public static partial class WinSpool
 		const string subKey64 = @"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Print\PackageInstallation\Windows x64\CorePrinterDrivers";
 
 		var is64bit = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("PROCESSOR_ARCHITEW6432"));
-		using var baseKey = string.IsNullOrEmpty(pszServer) ? null : RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, pszServer);
+		using var baseKey = string.IsNullOrEmpty(pszServer) ? null : RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, pszServer!);
 		using var reg = (baseKey ?? Registry.LocalMachine).OpenSubKey(is64bit ? subKey64 : subKey32, false);// RegistryKeyPermissionCheck.ReadSubTree, RegistryRights.EnumerateSubKeys);
 		var keys = reg?.GetSubKeyNames();
 		if (keys?.Length == 0) return new CORE_PRINTER_DRIVER[0];
-		var drvs = new CORE_PRINTER_DRIVER[keys.Length];
+		var drvs = new CORE_PRINTER_DRIVER[keys!.Length];
 		GetCorePrinterDrivers(pszServer, pszEnvironment, keys, (uint)keys.Length, drvs).ThrowIfFailed();
 		return drvs;
 	}
@@ -1011,19 +1011,8 @@ public static partial class WinSpool
 	/// <returns>A sequence of <c>MONITOR_INFO_1</c> structures or <c>MONITOR_INFO_2</c> structures.</returns>
 	/// <exception cref="System.ArgumentException"></exception>
 	[PInvokeData("winspool.h", MSDNShortId = "4d4fbed2-193f-426c-8463-eeb6b1eaf316")]
-	public static IEnumerable<T> EnumMonitors<T>([Optional] string? pName) where T : struct
-	{
-		if (!TryGetLevel<T>("MONITOR_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(EnumMonitors)} cannot process a structure of type {typeof(T).Name}.");
-		if (!EnumMonitors(pName, lvl, default, 0, out var bytes, out var count))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		if (bytes == 0)
-			return new T[0];
-		using var mem = new SafeCoTaskMemHandle(bytes);
-		if (!EnumMonitors(pName, lvl, mem, mem.Size, out bytes, out count))
-			Win32Error.ThrowLastError();
-		return mem.ToArray<T>((int)count);
-	}
+	public static IEnumerable<T> EnumMonitors<T>([Optional] string? pName) where T : struct =>
+		WSEnum<T>("MONITOR_INFO_", (uint l, IntPtr p, uint cb, out uint pcb, out uint c) => EnumMonitors(pName, l, p, cb, out pcb, out c));
 
 	/// <summary>The <c>EnumPorts</c> function enumerates the ports that are available for printing on a specified server.</summary>
 	/// <param name="pName">
@@ -1075,19 +1064,8 @@ public static partial class WinSpool
 	/// <returns>A sequence of <c>PORT_INFO_1</c> structures or <c>PORT_INFO_2</c> structures.</returns>
 	/// <remarks>The <c>EnumPorts</c> function can succeed even if the server specified by pName does not have a printer defined.</remarks>
 	[PInvokeData("winspool.h", MSDNShortId = "72ea0e35-bf26-4c12-9451-8f6941990d82")]
-	public static IEnumerable<T> EnumPorts<T>([Optional] string? pName) where T : struct
-	{
-		if (!TryGetLevel<T>("PORT_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(EnumPorts)} cannot process a structure of type {typeof(T).Name}.");
-		if (!EnumPorts(pName, lvl, default, 0, out var bytes, out var count))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		if (bytes == 0)
-			return new T[0];
-		using var mem = new SafeCoTaskMemHandle(bytes);
-		if (!EnumPorts(pName, lvl, mem, mem.Size, out bytes, out count))
-			Win32Error.ThrowLastError();
-		return mem.ToArray<T>((int)count);
-	}
+	public static IEnumerable<T> EnumPorts<T>([Optional] string? pName) where T : struct =>
+		WSEnum<T>("PORT_INFO_", (uint l, IntPtr p, uint cb, out uint pcb, out uint c) => EnumPorts(pName, l, p, cb, out pcb, out c));
 
 	/// <summary>The <c>EnumPrinterDrivers</c> function enumerates the printer drivers installed on a specified printer server.</summary>
 	/// <param name="pName">
@@ -1199,19 +1177,8 @@ public static partial class WinSpool
 	/// <c>DRIVER_INFO_6</c>, or <c>DRIVER_INFO_8</c> structures.
 	/// </returns>
 	[PInvokeData("winspool.h", MSDNShortId = "fa3d8cf4-70bc-4362-833e-e4217ed5d43b")]
-	public static IEnumerable<T> EnumPrinterDrivers<T>([Optional] string? pName, [Optional] string? pEnvironment) where T : struct
-	{
-		if (!TryGetLevel<T>("DRIVER_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(EnumPrinterDrivers)} cannot process a structure of type {typeof(T).Name}.");
-		if (!EnumPrinterDrivers(pName, pEnvironment, lvl, default, 0, out var bytes, out var count))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		if (bytes == 0)
-			return new T[0];
-		using var mem = new SafeCoTaskMemHandle(bytes);
-		if (!EnumPrinterDrivers(pName, pEnvironment, lvl, mem, mem.Size, out bytes, out count))
-			Win32Error.ThrowLastError();
-		return mem.ToArray<T>((int)count);
-	}
+	public static IEnumerable<T> EnumPrinterDrivers<T>([Optional] string? pName, [Optional] string? pEnvironment) where T : struct =>
+		WSEnum<T>("DRIVER_INFO_", (uint l, IntPtr p, uint cb, out uint pcb, out uint c) => EnumPrinterDrivers(pName, pEnvironment, l, p, cb, out pcb, out c));
 
 	/// <summary>The <c>EnumPrintProcessorDatatypes</c> function enumerates the data types that a specified print processor supports.</summary>
 	/// <param name="pName">
@@ -1271,19 +1238,8 @@ public static partial class WinSpool
 	/// <returns>A sequence of <c>DATATYPES_INFO_1</c> structures.</returns>
 	/// <remarks>Starting with Windows Vista, the data type information from remote print servers is retrieved from a local cache.</remarks>
 	[PInvokeData("winspool.h", MSDNShortId = "27b6e074-d303-446b-9e5f-6cfa55c30d26")]
-	public static IEnumerable<T> EnumPrintProcessorDatatypes<T>(string pPrintProcessorName, [Optional] string? pName) where T : struct
-	{
-		if (!TryGetLevel<T>("DATATYPES_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(EnumPrintProcessorDatatypes)} cannot process a structure of type {typeof(T).Name}.");
-		if (!EnumPrintProcessorDatatypes(pName, pPrintProcessorName, lvl, default, 0, out var bytes, out var count))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		if (bytes == 0)
-			return new T[0];
-		using var mem = new SafeCoTaskMemHandle(bytes);
-		if (!EnumPrintProcessorDatatypes(pName, pPrintProcessorName, lvl, mem, mem.Size, out bytes, out count))
-			Win32Error.ThrowLastError();
-		return mem.ToArray<T>((int)count);
-	}
+	public static IEnumerable<T> EnumPrintProcessorDatatypes<T>(string pPrintProcessorName, [Optional] string? pName) where T : struct =>
+		WSEnum<T>("DATATYPES_INFO_", (uint l, IntPtr p, uint cb, out uint pcb, out uint c) => EnumPrintProcessorDatatypes(pName, pPrintProcessorName, l, p, cb, out pcb, out c));
 
 	/// <summary>The <c>EnumPrintProcessors</c> function enumerates the print processors installed on the specified server.</summary>
 	/// <param name="pName">
@@ -1597,7 +1553,7 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = true, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "0d482d28-7668-4734-ba71-5b355c18ddec")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool GetPrinterDriver2([Optional] HWND hWnd, HPRINTER hPrinter, [Optional] string? pEnvironment, uint Level, IntPtr pDriverInfo, uint cbBuf, out uint pcbNeeded);
+	public static extern bool GetPrinterDriver2([Optional] HWND hWnd, HPRINTER hPrinter, [Optional] string? pEnvironment, uint Level, [Optional] IntPtr pDriverInfo, [Optional] uint cbBuf, out uint pcbNeeded);
 
 	/// <summary>
 	/// The <c>GetPrinterDriver2</c> function retrieves driver data for the specified printer. If the driver is not installed on the
@@ -1672,7 +1628,7 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "69c9cc87-d7e3-496a-b631-b3ae30cdb3fd")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool GetPrinterDriverDirectory([Optional] string? pName, [Optional] string? pEnvironment, uint Level, StringBuilder pDriverDirectory, int cbBuf, out int pcbNeeded);
+	public static extern bool GetPrinterDriverDirectory([Optional] string? pName, [Optional] string? pEnvironment, uint Level, StringBuilder? pDriverDirectory, int cbBuf, out int pcbNeeded);
 
 	/// <summary>Retrieves the path to the specified printer driver package on a print server.</summary>
 	/// <param name="pszServer">
@@ -1709,7 +1665,8 @@ public static partial class WinSpool
 	// pszDriverPackageCab, _In_ DWORD cchDriverPackageCab, _Out_ LPDWORD pcchRequiredSize );
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "e88e984b-d2c0-43b4-8f70-b05ec202ab14")]
-	public static extern HRESULT GetPrinterDriverPackagePath([Optional] string? pszServer, [Optional] string? pszEnvironment, [Optional] string? pszLanguage, string pszPackageID, StringBuilder pszDriverPackageCab, int cchDriverPackageCab, out int pcchRequiredSize);
+	public static extern HRESULT GetPrinterDriverPackagePath([Optional] string? pszServer, [Optional] string? pszEnvironment, [Optional] string? pszLanguage,
+		string pszPackageID, StringBuilder? pszDriverPackageCab, int cchDriverPackageCab, out int pcchRequiredSize);
 
 	/// <summary>
 	/// The <c>GetPrintProcessorDirectory</c> function retrieves the path to the print processor directory on the specified server.
@@ -1744,7 +1701,7 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "a2443cfd-e5ba-41c6-aaf4-45051a3d0e26")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool GetPrintProcessorDirectory([Optional] string? pName, [Optional] string? pEnvironment, uint Level, StringBuilder pPrintProcessorInfo, int cbBuf, out int pcbNeeded);
+	public static extern bool GetPrintProcessorDirectory([Optional] string? pName, [Optional] string? pEnvironment, uint Level, StringBuilder? pPrintProcessorInfo, int cbBuf, out int pcbNeeded);
 
 	/// <summary>Installs a printer driver from a driver package that is in the print server's driver store.</summary>
 	/// <param name="pszServer">

PInvoke/Printing/WinSpool.Funcs.cs

@@ -1,5 +1,8 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Security.Cryptography;
 
 namespace Vanara.PInvoke;
 
@@ -163,7 +166,7 @@ public static partial class WinSpool
 	/// print spooler that the print job can now be scheduled by the spooler for printing.
 	/// </remarks>
 	[PInvokeData("winspool.h", MSDNShortId = "cfafa874-6022-4bf4-bf3d-096213eb0c98")]
-	public static bool AddJob(HPRINTER hPrinter, out string path, out uint jobId)
+	public static bool AddJob(HPRINTER hPrinter, out string? path, out uint jobId)
 	{
 		path = null; jobId = 0;
 		AddJob(hPrinter, 1, default, 0, out var sz);
@@ -451,7 +454,7 @@ public static partial class WinSpool
 	// https://docs.microsoft.com/en-us/windows/win32/printdocs/addprinterconnection2 BOOL AddPrinterConnection2( _In_ HWND hWnd, _In_
 	// LPCTSTR pszName, DWORD dwLevel, _In_ PVOID pConnectionInfo );
 	[PInvokeData("winspool.h", MSDNShortId = "5ae98157-5978-449e-beb1-4787110925fa")]
-	public static bool AddPrinterConnection2([Optional] HWND hWnd, string pszName, PRINTER_CONNECTION_FLAGS flags, string driverName = null) =>
+	public static bool AddPrinterConnection2([Optional] HWND hWnd, string pszName, PRINTER_CONNECTION_FLAGS flags, string? driverName = null) =>
 		AddPrinterConnection2(hWnd, pszName, 1, new PRINTER_CONNECTION_INFO_1 { dwFlags = flags, pszDriverName = driverName });
 
 	/// <summary>
@@ -1909,7 +1912,7 @@ public static partial class WinSpool
 	// hPrinter, _In_ LPTSTR pDeviceName, _Out_ PDEVMODE pDevModeOutput, _In_ PDEVMODE pDevModeInput, _In_ DWORD fMode );
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "e89a2f6f-2bac-4369-b526-f8e15028698b")]
-	public static extern int DocumentProperties(HWND hWnd, HPRINTER hPrinter, string pDeviceName, IntPtr pDevModeOutput, in DEVMODE pDevModeInput, DM fMode);
+	public static extern int DocumentProperties(HWND hWnd, HPRINTER hPrinter, string pDeviceName, IntPtr pDevModeOutput, in DEVMODE pDevModeInput, [Optional] DM fMode);
 
 	/// <summary>
 	/// The <c>DocumentProperties</c> function retrieves or modifies printer initialization information or displays a
@@ -2034,7 +2037,7 @@ public static partial class WinSpool
 	// hPrinter, _In_ LPTSTR pDeviceName, _Out_ PDEVMODE pDevModeOutput, _In_ PDEVMODE pDevModeInput, _In_ DWORD fMode );
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "e89a2f6f-2bac-4369-b526-f8e15028698b")]
-	public static extern int DocumentProperties(HWND hWnd, HPRINTER hPrinter, string pDeviceName, IntPtr pDevModeOutput, [Optional] IntPtr pDevModeInput, DM fMode);
+	public static extern int DocumentProperties(HWND hWnd, HPRINTER hPrinter, string pDeviceName, IntPtr pDevModeOutput, [Optional] IntPtr pDevModeInput, [Optional] DM fMode);
 
 	/// <summary>The <c>EndDocPrinter</c> function ends a print job for the specified printer.</summary>
 	/// <param name="hPrinter">
@@ -2175,20 +2178,38 @@ public static partial class WinSpool
 	/// </param>
 	/// <returns>A sequence of <c>FORM_INFO_1</c> or <c>FORM_INFO_2</c> structures. All the structures will be of <typeparamref name="T"/>.</returns>
 	[PInvokeData("winspool.h", MSDNShortId = "b13b515a-c764-4a80-ab85-95fb4abb2a6b")]
-	public static IEnumerable<T> EnumForms<T>(HPRINTER hPrinter) where T : struct
+	public static IEnumerable<T> EnumForms<T>(HPRINTER hPrinter) where T : struct =>
+		WSEnum<T>("FORM_INFO_", (uint l, IntPtr p, uint cb, out uint pcb, out uint c) => EnumForms(hPrinter, l, p, cb, out pcb, out c));
+
+	private delegate bool F1(uint l, IntPtr p, uint cb, out uint pcb, out uint pcr);
+	private delegate bool T1(uint l, IntPtr p, uint cb, out uint pcb);
+
+	private static IEnumerable<T> WSEnum<T>(string prefix, F1 f, [CallerMemberName] string? caller = null) where T : struct
 	{
-		if (!TryGetLevel<T>("FORM_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(EnumForms)} cannot process a structure of type {typeof(T).Name}.");
-		if (!EnumForms(hPrinter, lvl, default, 0, out var bytes, out var count))
+		if (!TryGetLevel<T>(prefix, out var lvl))
+			throw new ArgumentException($"{caller} cannot process a structure of type {typeof(T).Name}.");
+		if (!f(lvl, default, 0, out var bytes, out var count))
 			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
 		if (bytes == 0)
 			return new T[0];
-		using var mem = new SafeCoTaskMemHandle(bytes);
-		if (!EnumForms(hPrinter, lvl, mem, mem.Size, out bytes, out count))
+		using SafeCoTaskMemHandle mem = new(bytes);
+		if (!f(lvl, mem, mem.Size, out bytes, out count))
 			Win32Error.ThrowLastError();
 		return mem.ToArray<T>((int)count);
 	}
 
+	private static T WSGet<T>(string prefix, T1 f, [CallerMemberName] string? caller = null) where T : struct
+	{
+		if (!TryGetLevel<T>(prefix, out var lvl))
+			throw new ArgumentException($"{caller} cannot process a structure of type {typeof(T).Name}.");
+		if (!f(lvl, default, 0, out var bytes))
+			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
+		using SafeCoTaskMemStruct<T> mem = new(bytes);
+		if (!f(lvl, mem, mem.Size, out bytes))
+			Win32Error.ThrowLastError();
+		return mem.Value;
+	}
+
 	/// <summary>The <c>EnumJobs</c> function retrieves information about a specified set of print jobs for a specified printer.</summary>
 	/// <param name="hPrinter">
 	/// A handle to the printer object whose print jobs the function enumerates. Use the <c>OpenPrinter</c> or <c>AddPrinter</c>
@@ -2279,19 +2300,8 @@ public static partial class WinSpool
 	/// A sequence of <c>JOB_INFO_1</c>, <c>JOB_INFO_2</c>, or <c>JOB_INFO_3</c> structures. All the structures will be of <typeparamref name="T"/>.
 	/// </returns>
 	[PInvokeData("winspool.h", MSDNShortId = "1cf429ea-b40e-4063-b6de-c43b7b87f3d3")]
-	public static IEnumerable<T> EnumJobs<T>(HPRINTER hPrinter, uint FirstJob = 0, uint NoJobs = uint.MaxValue) where T : struct
-	{
-		if (!TryGetLevel<T>("JOB_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(EnumJobs)} cannot process a structure of type {typeof(T).Name}.");
-		if (!EnumJobs(hPrinter, FirstJob, NoJobs, lvl, default, 0, out var bytes, out var count))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		if (bytes == 0)
-			return new T[0];
-		using var mem = new SafeCoTaskMemHandle(bytes);
-		if (!EnumJobs(hPrinter, FirstJob, NoJobs, lvl, mem, mem.Size, out bytes, out count))
-			Win32Error.ThrowLastError();
-		return mem.ToArray<T>((int)count);
-	}
+	public static IEnumerable<T> EnumJobs<T>(HPRINTER hPrinter, uint FirstJob = 0, uint NoJobs = uint.MaxValue) where T : struct =>
+		WSEnum<T>("JOB_INFO_", (uint l, IntPtr p, uint cb, out uint pcb, out uint c) => EnumJobs(hPrinter, FirstJob, NoJobs, l, p, cb, out pcb, out c));
 
 	/// <summary>
 	/// <para>The <c>EnumPrinterData</c> function enumerates configuration data for a specified printer.</para>
@@ -2385,8 +2395,8 @@ public static partial class WinSpool
 	// _In_ DWORD cbData, _Out_ LPDWORD pcbData );
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "0a4c8436-46fe-4e21-8d55-c5031a3d1b38")]
-	public static extern Win32Error EnumPrinterData(HPRINTER hPrinter, uint dwIndex, StringBuilder pValueName, uint cbValueName,
-		out uint pcbValueName, out REG_VALUE_TYPE pType, IntPtr pData, uint cbData, out uint pcbData);
+	public static extern Win32Error EnumPrinterData(HPRINTER hPrinter, uint dwIndex, StringBuilder? pValueName, uint cbValueName,
+		out uint pcbValueName, out REG_VALUE_TYPE pType, [Optional] IntPtr pData, uint cbData, out uint pcbData);
 
 	/// <summary>
 	/// <para>The <c>EnumPrinterData</c> function enumerates configuration data for a specified printer.</para>
@@ -2414,7 +2424,7 @@ public static partial class WinSpool
 	/// </list>
 	/// </returns>
 	[PInvokeData("winspool.h", MSDNShortId = "0a4c8436-46fe-4e21-8d55-c5031a3d1b38")]
-	public static IEnumerable<(string valueName, REG_VALUE_TYPE valueType, object value)> EnumPrinterData(HPRINTER hPrinter)
+	public static IEnumerable<(string valueName, REG_VALUE_TYPE valueType, object? value)> EnumPrinterData(HPRINTER hPrinter)
 	{
 		var idx = 0U;
 		EnumPrinterData(hPrinter, idx, null, 0, out var valueNameSz, out _, default, 0, out var dataSz).ThrowIfFailed();
@@ -2517,7 +2527,7 @@ public static partial class WinSpool
 	/// </list>
 	/// </returns>
 	[PInvokeData("winspool.h", MSDNShortId = "bc5ecc46-24a4-4b54-9431-0eaf6446e2d6")]
-	public static IEnumerable<(string valueName, REG_VALUE_TYPE valueType, object value)> EnumPrinterDataEx(HPRINTER hPrinter, string pKeyName = "PrinterDriverData")
+	public static IEnumerable<(string valueName, REG_VALUE_TYPE valueType, object? value)> EnumPrinterDataEx(HPRINTER hPrinter, string pKeyName = "PrinterDriverData")
 	{
 		EnumPrinterDataEx(hPrinter, pKeyName, default, 0, out var sz, out var cnt).ThrowUnless(Win32Error.ERROR_MORE_DATA);
 		using var mem = new SafeCoTaskMemHandle(sz);
@@ -2828,7 +2838,7 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = true, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "0d0cc726-c515-4146-9273-cdf1db3c76b7")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool EnumPrinters(PRINTER_ENUM Flags, string Name, uint Level, IntPtr pPrinterEnum, uint cbBuf, out uint pcbNeeded, out uint pcReturned);
+	public static extern bool EnumPrinters(PRINTER_ENUM Flags, string? Name, uint Level, IntPtr pPrinterEnum, uint cbBuf, out uint pcbNeeded, out uint pcReturned);
 
 	/// <summary>The <c>EnumPrinters</c> function enumerates available printers, print servers, domains, or print providers.</summary>
 	/// <typeparam name="T">
@@ -2921,19 +2931,8 @@ public static partial class WinSpool
 	/// </para>
 	/// </returns>
 	[PInvokeData("winspool.h", MSDNShortId = "0d0cc726-c515-4146-9273-cdf1db3c76b7")]
-	public static IEnumerable<T> EnumPrinters<T>(PRINTER_ENUM Flags = PRINTER_ENUM.PRINTER_ENUM_LOCAL, string Name = null) where T : struct
-	{
-		if (!TryGetLevel<T>("PRINTER_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(EnumPrinters)} cannot process a structure of type {typeof(T).Name}.");
-		if (!EnumPrinters(Flags, Name, lvl, default, 0, out var bytes, out var count))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		if (bytes == 0)
-			return new T[0];
-		using var mem = new SafeCoTaskMemHandle(bytes);
-		if (!EnumPrinters(Flags, Name, lvl, mem, mem.Size, out bytes, out count))
-			Win32Error.ThrowLastError();
-		return mem.ToArray<T>((int)count);
-	}
+	public static IEnumerable<T> EnumPrinters<T>(PRINTER_ENUM Flags = PRINTER_ENUM.PRINTER_ENUM_LOCAL, string? Name = null) where T : struct =>
+		WSEnum<T>("PRINTER_INFO_", (uint l, IntPtr p, uint cb, out uint pcb, out uint c) => EnumPrinters(Flags, Name, l, p, cb, out pcb, out c));
 
 	/// <summary>
 	/// The <c>FindClosePrinterChangeNotification</c> function closes a change notification object created by calling the
@@ -3777,7 +3776,7 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = true, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "8ec06743-43ce-4fac-83c4-f09eac7ee333")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool GetDefaultPrinter(StringBuilder pszBuffer, ref int pcchBuffer);
+	public static extern bool GetDefaultPrinter(StringBuilder? pszBuffer, ref int pcchBuffer);
 
 	/// <summary>The <c>GetForm</c> function retrieves information about a specified form.</summary>
 	/// <param name="hPrinter">
@@ -3823,17 +3822,8 @@ public static partial class WinSpool
 	/// If the caller is remote, and the Level is 2, the <c>StringType</c> value of the returned <c>FORM_INFO_2</c> will always be STRING_LANGPAIR.
 	/// </remarks>
 	[PInvokeData("winspool.h", MSDNShortId = "10b25748-6d7c-46ab-bd2c-9b6126a1d7d1")]
-	public static T GetForm<T>(HPRINTER hPrinter, string pFormName) where T : struct
-	{
-		if (!TryGetLevel<T>("FORM_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(GetForm)} cannot process a structure of type {typeof(T).Name}.");
-		if (!GetForm(hPrinter, pFormName, lvl, default, 0, out var sz))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		using var mem = new SafeCoTaskMemHandle(sz);
-		if (!GetForm(hPrinter, pFormName, lvl, mem, mem.Size, out sz))
-			Win32Error.ThrowLastError();
-		return mem.ToStructure<T>();
-	}
+	public static T GetForm<T>(HPRINTER hPrinter, string pFormName) where T : struct =>
+		WSGet<T>("FORM_INFO_", (uint l, IntPtr p, uint cb, out uint pcb) => GetForm(hPrinter, pFormName, l, p, cb, out pcb));
 
 	/// <summary>The <c>GetJob</c> function retrieves information about a specified print job.</summary>
 	/// <param name="hPrinter">
@@ -3889,17 +3879,8 @@ public static partial class WinSpool
 	/// <returns>A <c>JOB_INFO_1</c> or a <c>JOB_INFO_2</c> structure containing information about the job as specified by <typeparamref name="T"/>.</returns>
 	/// <exception cref="ArgumentException"></exception>
 	[PInvokeData("winspool.h", MSDNShortId = "57e59f84-d2a0-4722-b0fc-6673f7bb5c57")]
-	public static T GetJob<T>(HPRINTER hPrinter, uint JobId) where T : struct
-	{
-		if (!TryGetLevel<T>("JOB_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(GetJob)} cannot process a structure of type {typeof(T).Name}.");
-		if (!GetJob(hPrinter, JobId, lvl, default, 0, out var sz))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		using var mem = new SafeCoTaskMemHandle(sz);
-		if (!GetJob(hPrinter, JobId, lvl, mem, mem.Size, out sz))
-			Win32Error.ThrowLastError();
-		return mem.ToStructure<T>();
-	}
+	public static T GetJob<T>(HPRINTER hPrinter, uint JobId) where T : struct =>
+		WSGet<T>("JOB_INFO_", (uint l, IntPtr p, uint cb, out uint pcb) => GetJob(hPrinter, JobId, l, p, cb, out pcb));
 
 	/// <summary>The <c>GetPrinter</c> function retrieves information about a specified printer.</summary>
 	/// <param name="hPrinter">
@@ -4112,17 +4093,8 @@ public static partial class WinSpool
 	/// configurations, the printer data is queried from the print server.
 	/// </para>
 	/// </remarks>
-	public static T GetPrinter<T>(HPRINTER hPrinter) where T : struct
-	{
-		if (!TryGetLevel<T>("PRINTER_INFO_", out var lvl))
-			throw new ArgumentException($"{nameof(GetPrinter)} cannot process a structure of type {typeof(T).Name}.");
-		if (!GetPrinter(hPrinter, lvl, default, 0, out var sz))
-			Win32Error.ThrowLastErrorUnless(Win32Error.ERROR_INSUFFICIENT_BUFFER);
-		using var mem = new SafeCoTaskMemHandle(sz);
-		if (!GetPrinter(hPrinter, lvl, mem, mem.Size, out sz))
-			Win32Error.ThrowLastError();
-		return mem.ToStructure<T>();
-	}
+	public static T GetPrinter<T>(HPRINTER hPrinter) where T : struct =>
+		WSGet<T>("PRINTER_INFO_", (uint l, IntPtr p, uint cb, out uint pcb) => GetPrinter(hPrinter, l, p, cb, out pcb));
 
 	/// <summary>
 	/// <para>The <c>GetPrinterData</c> function retrieves configuration data for the specified printer or print server.</para>
@@ -4578,7 +4550,7 @@ public static partial class WinSpool
 	/// </list>
 	/// </remarks>
 	[PInvokeData("winspool.h", MSDNShortId = "b5a44b27-a4aa-4e58-9a64-05be87d12ab5")]
-	public static object GetPrinterData(HPRINTER hPrinter, string pValueName)
+	public static object? GetPrinterData(HPRINTER hPrinter, string pValueName)
 	{
 		GetPrinterData(hPrinter, pValueName, out _, default, 0, out var sz).ThrowUnless(Win32Error.ERROR_MORE_DATA);
 		using var mem = new SafeCoTaskMemHandle(sz);
@@ -5068,7 +5040,7 @@ public static partial class WinSpool
 	/// </list>
 	/// </remarks>
 	[PInvokeData("winspool.h", MSDNShortId = "5d9183a7-97cc-46de-848e-e37ce51396eb")]
-	public static object GetPrinterDataEx(HPRINTER hPrinter, string pKeyName, string pValueName)
+	public static object? GetPrinterDataEx(HPRINTER hPrinter, string pKeyName, string pValueName)
 	{
 		GetPrinterDataEx(hPrinter, pKeyName, pValueName, out _, default, 0, out var sz).ThrowUnless(Win32Error.ERROR_MORE_DATA);
 		using var mem = new SafeCoTaskMemHandle(sz);
@@ -5252,8 +5224,8 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = true, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "96763220-d851-46f0-8be8-403f3356edb9")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool OpenPrinter(string pPrinterName, out SafeHPRINTER phPrinter,
-		[In, Optional, MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(PRINTER_DEFAULTS_Marshaler))] PRINTER_DEFAULTS pDefault);
+	public static extern bool OpenPrinter(string? pPrinterName, out SafeHPRINTER phPrinter,
+		[In, Optional, MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(PRINTER_DEFAULTS_Marshaler))] PRINTER_DEFAULTS? pDefault);
 
 	/// <summary>
 	/// Retrieves a handle to the specified printer, print server, or other types of handles in the print subsystem, while setting some
@@ -5345,8 +5317,101 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = true, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "e2370ae4-4475-4ccc-a6f9-3d33d1370054")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool OpenPrinter2(string pPrinterName, out SafeHPRINTER phPrinter,
-		[In, Optional, MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(PRINTER_DEFAULTS_Marshaler))] PRINTER_DEFAULTS pDefault, in PRINTER_OPTIONS pOptions);
+	public static extern bool OpenPrinter2(string? pPrinterName, out SafeHPRINTER phPrinter,
+		[In, Optional, MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(PRINTER_DEFAULTS_Marshaler))] PRINTER_DEFAULTS? pDefault, in PRINTER_OPTIONS pOptions);
+
+	/// <summary>
+	/// Retrieves a handle to the specified printer, print server, or other types of handles in the print subsystem, while setting some
+	/// of the printer options.
+	/// </summary>
+	/// <param name="pPrinterName">
+	/// <para>
+	/// A pointer to a constant null-terminated string that specifies the name of the printer or print server, the printer object, the
+	/// XcvMonitor, or the XcvPort.
+	/// </para>
+	/// <para>
+	/// For a printer object, use: PrinterName,Job xxxx. For an XcvMonitor, use: ServerName,XcvMonitor MonitorName. For an XcvPort, use:
+	/// ServerName,XcvPort PortName.
+	/// </para>
+	/// <para><c>Windows Vista:</c> If <c>NULL</c>, it indicates the local print server.</para>
+	/// </param>
+	/// <param name="phPrinter">A pointer to a variable that receives a handle to the open printer or print server object.</param>
+	/// <param name="pDefault">A pointer to a <c>PRINTER_DEFAULTS</c> structure. This value can be <c>NULL</c>.</param>
+	/// <param name="pOptions">A pointer to a <c>PRINTER_OPTIONS</c> structure. This value can be <c>NULL</c>.</param>
+	/// <returns>
+	/// <para>If the function succeeds, the return value is a nonzero value.</para>
+	/// <para>If the function fails, the return value is zero. For extended error information, call <c>GetLastError</c>.</para>
+	/// </returns>
+	/// <remarks>
+	/// <para>Do not call this method in <c>DllMain</c>.</para>
+	/// <para>The ANSI version of this function is not implemented and returns ERROR_NOT_SUPPORTED.</para>
+	/// <para>
+	/// The pDefault parameter enables you to specify the data type and device mode values that are used for printing documents
+	/// submitted by the <c>StartDocPrinter</c> function. However, you can override these values by using the <c>SetJob</c> function
+	/// after a document has been started.
+	/// </para>
+	/// <para>
+	/// You can call the <c>OpenPrinter2</c> function to open a handle to a print server or to determine client access rights to a print
+	/// server. To do this, specify the name of the print server in the pPrinterName parameter, set the <c>pDatatype</c> and
+	/// <c>pDevMode</c> members of the <c>PRINTER_DEFAULTS</c> structure to <c>NULL</c>, and set the <c>DesiredAccess</c> member to
+	/// specify a server access mask value such as SERVER_ALL_ACCESS. When you are finished with the handle, pass it to the
+	/// <c>ClosePrinter</c> function to close it.
+	/// </para>
+	/// <para>
+	/// Use the <c>DesiredAccess</c> member of the <c>PRINTER_DEFAULTS</c> structure to specify the necessary access rights. The access
+	/// rights can be one of the following.
+	/// </para>
+	/// <list type="table">
+	/// <listheader>
+	/// <term>Desired Access value</term>
+	/// <term>Meaning</term>
+	/// </listheader>
+	/// <item>
+	/// <term>PRINTER_ACCESS_ADMINISTER</term>
+	/// <term>To perform administrative tasks, such as those provided by SetPrinter.</term>
+	/// </item>
+	/// <item>
+	/// <term>PRINTER_ACCESS_USE</term>
+	/// <term>To perform basic printing operations.</term>
+	/// </item>
+	/// <item>
+	/// <term>PRINTER_ALL_ACCESS</term>
+	/// <term>To perform all administrative tasks and basic printing operations except SYNCHRONIZE. See Standard Access Rights.</term>
+	/// </item>
+	/// <item>
+	/// <term>PRINTER_ACCESS_MANAGE_LIMITED</term>
+	/// <term>
+	/// To perform administrative tasks, such as those provided by SetPrinter and SetPrinterData. This value is available starting from
+	/// Windows 8.1.
+	/// </term>
+	/// </item>
+	/// <item>
+	/// <term>generic security values, such as WRITE_DAC</term>
+	/// <term>To allow specific control access rights. See Standard Access Rights.</term>
+	/// </item>
+	/// </list>
+	/// <para>
+	/// If a user does not have permission to open a specified printer or print server with the desired access, the <c>OpenPrinter2</c>
+	/// call will fail, and <c>GetLastError</c> will return the value ERROR_ACCESS_DENIED.
+	/// </para>
+	/// <para>
+	/// When pPrinterName is a local printer, then <c>OpenPrinter2</c> ignores all values of the <c>dwFlags</c> that the
+	/// <c>PRINTER_OPTIONS</c> structure pointed to using pOptions, except PRINTER_OPTION_CLIENT_CHANGE. If the latter is passed, then
+	/// <c>OpenPrinter2</c> will return ERROR_ACCESS_DENIED. Accordingly, when opening a local printer, <c>OpenPrinter2</c> provides no
+	/// advantage over <c>OpenPrinter</c>.
+	/// </para>
+	/// <para>
+	/// <c>Windows Vista:</c> The printer data returned by <c>OpenPrinter2</c> is retrieved from a local cache unless the
+	/// <c>PRINTER_OPTION_NO_CACHE</c> flag is set in the <c>dwFlags</c> field of the <c>PRINTER_OPTIONS</c> structure referenced by pOptions.
+	/// </para>
+	/// </remarks>
+	// https://docs.microsoft.com/en-us/windows/win32/printdocs/openprinter2 BOOL OpenPrinter2( _In_ LPCTSTR pPrinterName, _Out_
+	// LPHANDLE phPrinter, _In_ LPPRINTER_DEFAULTS pDefault, _In_ PPRINTER_OPTIONS pOptions );
+	[DllImport(Lib.Winspool, SetLastError = true, CharSet = CharSet.Auto)]
+	[PInvokeData("winspool.h", MSDNShortId = "e2370ae4-4475-4ccc-a6f9-3d33d1370054")]
+	[return: MarshalAs(UnmanagedType.Bool)]
+	public static extern bool OpenPrinter2(string? pPrinterName, out SafeHPRINTER phPrinter,
+		[In, Optional, MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(PRINTER_DEFAULTS_Marshaler))] PRINTER_DEFAULTS? pDefault, [In, Optional] IntPtr pOptions);
 
 	/// <summary>The <c>PrinterProperties</c> function displays a printer-properties property sheet for the specified printer.</summary>
 	/// <param name="hWnd">A handle to the parent window of the property sheet.</param>
@@ -5499,7 +5564,7 @@ public static partial class WinSpool
 	[DllImport(Lib.Winspool, SetLastError = true, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "55eec548-577f-422b-80e3-8b23aa4d2159")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool SetDefaultPrinter(string pszPrinter);
+	public static extern bool SetDefaultPrinter(string? pszPrinter);
 
 	/// <summary>The <c>SetForm</c> function sets the form information for the specified printer.</summary>
 	/// <param name="hPrinter">
@@ -5976,7 +6041,7 @@ public static partial class WinSpool
 	[PInvokeData("winspool.h", MSDNShortId = "1b80ad93-aaa1-41ed-a668-a944fa62c3eb")]
 	public static bool SetPort([Optional] string? pName, string pPortName, PORT_STATUS status, PORT_STATUS_TYPE severity)
 	{
-		using var mem = SafeCoTaskMemHandle.CreateFromStructure(new PORT_INFO_3 { dwStatus = status, dwSeverity = severity });
+		using SafeCoTaskMemStruct<PORT_INFO_3> mem = new PORT_INFO_3 { dwStatus = status, dwSeverity = severity };
 		return SetPort(pName, pPortName, 3, mem);
 	}
 
@@ -6008,7 +6073,7 @@ public static partial class WinSpool
 	[PInvokeData("winspool.h", MSDNShortId = "1b80ad93-aaa1-41ed-a668-a944fa62c3eb")]
 	public static bool SetPort([Optional] string? pName, string pPortName, string status, PORT_STATUS_TYPE severity)
 	{
-		using var mem = SafeCoTaskMemHandle.CreateFromStructure(new PORT_INFO_3 { pszStatus = status, dwSeverity = severity });
+		using SafeCoTaskMemStruct<PORT_INFO_3> mem = new PORT_INFO_3 { pszStatus = status, dwSeverity = severity };
 		return SetPort(pName, pPortName, 3, mem);
 	}
 
@@ -6988,7 +7053,7 @@ public static partial class WinSpool
 	{
 		return InlineSetPrinterData(SetData, hPrinter, null, pValueName, pData, type);
 
-		static Win32Error SetData(HPRINTER p1, string p2, string p3, REG_VALUE_TYPE p4, IntPtr p5, uint p6) =>
+		static Win32Error SetData(HPRINTER p1, string? p2, string p3, REG_VALUE_TYPE p4, IntPtr p5, uint p6) =>
 			SetPrinterData(p1, p3, p4, p5, p6);
 	}
 
@@ -7226,7 +7291,7 @@ public static partial class WinSpool
 	// LPCTSTR pKeyName, _In_ LPCTSTR pValueName, _In_ DWORD Type, _In_ LPBYTE pData, _In_ DWORD cbData );
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "b7faadfc-1c81-4ddf-8fe5-68f4cc0376f1")]
-	public static extern Win32Error SetPrinterDataEx(HPRINTER hPrinter, string pKeyName, string pValueName, REG_VALUE_TYPE Type, IntPtr pData, uint cbData);
+	public static extern Win32Error SetPrinterDataEx(HPRINTER hPrinter, string? pKeyName, string pValueName, REG_VALUE_TYPE Type, IntPtr pData, uint cbData);
 
 	/// <summary>
 	/// The <c>SetPrinterDataEx</c> function sets the configuration data for a printer or print server. The function stores the
@@ -7462,7 +7527,7 @@ public static partial class WinSpool
 	// LPCTSTR pKeyName, _In_ LPCTSTR pValueName, _In_ DWORD Type, _In_ LPBYTE pData, _In_ DWORD cbData );
 	[DllImport(Lib.Winspool, SetLastError = false, CharSet = CharSet.Auto)]
 	[PInvokeData("winspool.h", MSDNShortId = "b7faadfc-1c81-4ddf-8fe5-68f4cc0376f1")]
-	public static extern Win32Error SetPrinterDataEx(HPRINTER hPrinter, string pKeyName, string pValueName, REG_VALUE_TYPE Type, byte[] pData, uint cbData);
+	public static extern Win32Error SetPrinterDataEx(HPRINTER hPrinter, string? pKeyName, string pValueName, REG_VALUE_TYPE Type, byte[] pData, uint cbData);
 
 	/// <summary>
 	/// The <c>SetPrinterDataEx</c> function sets the configuration data for a printer or print server. The function stores the
@@ -7694,7 +7759,7 @@ public static partial class WinSpool
 	/// </list>
 	/// </remarks>
 	[PInvokeData("winspool.h", MSDNShortId = "b7faadfc-1c81-4ddf-8fe5-68f4cc0376f1")]
-	public static Win32Error SetPrinterDataEx(HPRINTER hPrinter, string pKeyName, string pValueName, object pData, REG_VALUE_TYPE type = 0) =>
+	public static Win32Error SetPrinterDataEx(HPRINTER hPrinter, string? pKeyName, string pValueName, object pData, REG_VALUE_TYPE type = 0) =>
 		InlineSetPrinterData(SetPrinterDataEx, hPrinter, pKeyName, pValueName, pData, type);
 
 	/// <summary>The <c>StartDocPrinter</c> function notifies the print spooler that a document is to be spooled for printing.</summary>
@@ -7903,7 +7968,7 @@ public static partial class WinSpool
 	[return: MarshalAs(UnmanagedType.Bool)]
 	private static extern bool AddPrinterConnection2([Optional] HWND hWnd, string pszName, uint dwLevel, in PRINTER_CONNECTION_INFO_1 pConnectionInfo);
 
-	private static Win32Error InlineSetPrinterData(Func<HPRINTER, string, string, REG_VALUE_TYPE, IntPtr, uint, Win32Error> f, HPRINTER hPrinter, string pKeyName, string pValueName, object pData, REG_VALUE_TYPE type)
+	private static Win32Error InlineSetPrinterData(Func<HPRINTER, string?, string, REG_VALUE_TYPE, IntPtr, uint, Win32Error> f, HPRINTER hPrinter, string? pKeyName, string pValueName, object pData, REG_VALUE_TYPE type)
 	{
 		var pDataType = pData.GetType();
 		if (type == 0) type = RegistryTypeExt.GetFromType(pDataType);

PInvoke/Printing/WinSpool.Structs.cs

@@ -71,7 +71,7 @@ public static partial class WinSpool
 		/// Pointer to a null-terminated string that specifies the name of an output file. To print to a printer, set this to <c>NULL</c>.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pOutputFile;
+		public string? pOutputFile;
 
 		/// <summary>Pointer to a null-terminated string that identifies the type of data used to record the document.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
@@ -273,7 +273,7 @@ public static partial class WinSpool
 		/// <c>NULL</c> and should be specified only for printers capable of bidirectional communication.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pMonitorName;
+		public string? pMonitorName;
 
 		/// <summary>A pointer to a null-terminated string that specifies the default data type of the print job (for example, "EMF").</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
@@ -343,7 +343,7 @@ public static partial class WinSpool
 		/// <c>NULL</c> and should be specified only for printers capable of bidirectional communication.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pMonitorName;
+		public string? pMonitorName;
 
 		/// <summary>A pointer to a null-terminated string that specifies the default data type of the print job (for example, EMF).</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
@@ -486,7 +486,7 @@ public static partial class WinSpool
 		/// <c>NULL</c> and should be specified only for printers capable of bidirectional communication.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pMonitorName;
+		public string? pMonitorName;
 
 		/// <summary>A pointer to a null-terminated string that specifies the default data type of the print job (for example, "EMF").</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
@@ -507,21 +507,21 @@ public static partial class WinSpool
 
 		/// <summary>Pointer to a null-terminated string that specifies the manufacturer's name.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszMfgName;
+		public string? pszMfgName;
 
 		/// <summary>Pointer to a null-terminated string that specifies the URL for the manufacturer.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszOEMUrl;
+		public string? pszOEMUrl;
 
 		/// <summary>Pointer to a null-terminated string that specifies the hardware ID for the printer driver.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszHardwareID;
+		public string? pszHardwareID;
 
 		/// <summary>
 		/// Pointer to a null-terminated string that specifies the provider of the printer driver (for example, "Microsoft Windows 2000")
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszProvider;
+		public string? pszProvider;
 	}
 
 	/// <summary>Contains printer driver information.</summary>
@@ -591,7 +591,7 @@ public static partial class WinSpool
 		/// <c>NULL</c> and should be specified only for printers capable of bidirectional communication.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pMonitorName;
+		public string? pMonitorName;
 
 		/// <summary>A pointer to a null-terminated string that specifies the default data type of the print job (for example, "EMF").</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
@@ -612,21 +612,21 @@ public static partial class WinSpool
 
 		/// <summary>A pointer to a null-terminated string that specifies the manufacturer's name.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszMfgName;
+		public string? pszMfgName;
 
 		/// <summary>A pointer to a null-terminated string that specifies the URL for the manufacturer.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszOEMUrl;
+		public string? pszOEMUrl;
 
 		/// <summary>A pointer to a null-terminated string that specifies the hardware ID for the printer driver.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszHardwareID;
+		public string? pszHardwareID;
 
 		/// <summary>
 		/// A pointer to a null-terminated string that specifies the provider of the printer driver (for example, "Microsoft Windows 2000").
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszProvider;
+		public string? pszProvider;
 
 		/// <summary>A pointer to a null-terminated string that specifies the print processor (for example, "WinPrint").</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
@@ -645,7 +645,7 @@ public static partial class WinSpool
 		/// This must be <c>NULL</c> if the DRIVER_INFO_8 is being passed to <c>AddPrinterDriver</c> or <c>AddPrinterDriverEx</c>.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszInfPath;
+		public string? pszInfPath;
 
 		/// <summary>
 		/// <para>
@@ -730,7 +730,7 @@ public static partial class WinSpool
 		/// must be <c>NULL</c> if the <c>DRIVER_INFO_8</c> is being passed to <c>AddPrinterDriver</c> or <c>AddPrinterDriverEx</c>.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszzCoreDriverDependencies;
+		public string? pszzCoreDriverDependencies;
 
 		/// <summary>The earliest allowed date of any drivers that shipped with Windows and on which this driver depends.</summary>
 		public FILETIME ftMinInboxDriverVerDate;
@@ -909,14 +909,14 @@ public static partial class WinSpool
 
 		/// <summary>The Multilingual User Interface localized resource DLL that contains the localized display name.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pMuiDll;
+		public string? pMuiDll;
 
 		/// <summary>The resource ID of the form's display name in <c>pMuiDll</c>.</summary>
 		public uint dwResourceId;
 
 		/// <summary>The form's display name in the language specified by <c>wLangId</c>.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pDisplayName;
+		public string? pDisplayName;
 
 		/// <summary>The language of the <c>pDisplayName</c>.</summary>
 		public ushort wLangId;
@@ -961,7 +961,7 @@ public static partial class WinSpool
 		public static bool operator ==(HPRINTER h1, HPRINTER h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object? obj) => obj is HPRINTER h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HPRINTER h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();
@@ -1009,7 +1009,7 @@ public static partial class WinSpool
 		public static bool operator ==(HPRINTERCHANGENOTIFICATION h1, HPRINTERCHANGENOTIFICATION h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object? obj) => obj is HPRINTERCHANGENOTIFICATION h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HPRINTERCHANGENOTIFICATION h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();
@@ -1057,7 +1057,7 @@ public static partial class WinSpool
 		public static bool operator ==(HSPOOLFILE h1, HSPOOLFILE h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object? obj) => obj is HSPOOLFILE h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HSPOOLFILE h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();
@@ -1109,7 +1109,7 @@ public static partial class WinSpool
 		/// Status and, if pStatus is <c>NULL</c>, the status is defined by the contents of the Status member.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pStatus;
+		public string? pStatus;
 
 		/// <summary>
 		/// <para>
@@ -1304,7 +1304,7 @@ public static partial class WinSpool
 		/// <c>Status</c> and, if <c>pStatus</c> is <c>NULL</c>, the status is defined by the contents of the Status member.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pStatus;
+		public string? pStatus;
 
 		/// <summary>
 		/// The value of this member is <c>NULL</c>. Retrieval and setting of document security descriptors is not supported in this release.
@@ -1537,7 +1537,7 @@ public static partial class WinSpool
 		/// <c>Status</c> and, if <c>pStatus</c> is <c>NULL</c>, the status is defined by the contents of the Status member.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pStatus;
+		public string? pStatus;
 
 		/// <summary>
 		/// The value of this member is <c>NULL</c>. Retrieval and setting of document security descriptors is not supported in this release.
@@ -1762,7 +1762,7 @@ public static partial class WinSpool
 		/// <c>pDescription</c> is "printer port"). This can be <c>NULL</c>.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pDescription;
+		public string? pDescription;
 
 		/// <summary>Bitmask describing the type of port. This member can be a combination of the following values:</summary>
 		public PORT_TYPE fPortType;
@@ -1932,7 +1932,7 @@ public static partial class WinSpool
 
 		/// <summary>A pointer to the name of the driver.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszDriverName;
+		public string? pszDriverName;
 	}
 
 	/// <summary>
@@ -2041,7 +2041,7 @@ public static partial class WinSpool
 
 		/// <summary>Pointer to a null-terminated string that contains additional data describing the structure.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pComment;
+		public string? pComment;
 	}
 
 	/// <summary>The <c>PRINTER_INFO_2</c> structure specifies detailed printer information.</summary>
@@ -2059,7 +2059,7 @@ public static partial class WinSpool
 		/// printer is controlled locally.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pServerName;
+		public string? pServerName;
 
 		/// <summary>A pointer to a null-terminated string that specifies the name of the printer.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
@@ -2070,7 +2070,7 @@ public static partial class WinSpool
 		/// PRINTER_ATTRIBUTE_SHARED constant was set for the <c>Attributes</c> member.)
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pShareName;
+		public string? pShareName;
 
 		/// <summary>
 		/// A pointer to a null-terminated string that identifies the port(s) used to transmit data to the printer. If a printer is
@@ -2085,13 +2085,13 @@ public static partial class WinSpool
 
 		/// <summary>A pointer to a null-terminated string that provides a brief description of the printer.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pComment;
+		public string? pComment;
 
 		/// <summary>
 		/// A pointer to a null-terminated string that specifies the physical location of the printer (for example, "Bldg. 38, Room 1164").
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pLocation;
+		public string? pLocation;
 
 		/// <summary>
 		/// A pointer to a <c>DEVMODE</c> structure that defines default printer data such as the paper orientation and the resolution.
@@ -2103,7 +2103,7 @@ public static partial class WinSpool
 		/// used to separate print jobs sent to the printer.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pSepFile;
+		public string? pSepFile;
 
 		/// <summary>
 		/// A pointer to a null-terminated string that specifies the name of the print processor used by the printer. You can use the
@@ -2117,11 +2117,11 @@ public static partial class WinSpool
 		/// <c>EnumPrintProcessorDatatypes</c> function to obtain a list of data types supported by a specific print processor.
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pDatatype;
+		public string? pDatatype;
 
 		/// <summary>A pointer to a null-terminated string that specifies the default print-processor parameters.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pParameters;
+		public string? pParameters;
 
 		/// <summary>A pointer to a <c>SECURITY_DESCRIPTOR</c> structure for the printer. This member may be <c>NULL</c>.</summary>
 		public PSECURITY_DESCRIPTOR pSecurityDescriptor;
@@ -2431,7 +2431,7 @@ public static partial class WinSpool
 
 		/// <summary>Pointer to a null-terminated string that is the name of the server.</summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pServerName;
+		public string? pServerName;
 
 		/// <summary>
 		/// <para>Specifies information about the returned data.</para>
@@ -2730,7 +2730,7 @@ public static partial class WinSpool
 		/// <para>Before calling <c>SetPrinter</c>, set <c>pszObjectGUID</c> to <c>NULL</c>.</para>
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string pszObjectGUID;
+		public string? pszObjectGUID;
 
 		/// <summary>
 		/// <para>
@@ -3612,7 +3612,7 @@ public static partial class WinSpool
 		public ACCESS_MASK DesiredAccess;
 
 		/// <summary>Pointer to a null-terminated string that specifies the default data type for a printer.</summary>
-		public string pDatatype;
+		public string? pDatatype;
 
 		/// <summary>A <c>DEVMODE</c> structure that identifies the default environment and initialization data for a printer.</summary>
 		public DEVMODE? pDevMode;
@@ -3733,14 +3733,14 @@ public static partial class WinSpool
 
 		public IntPtr MarshalManagedToNative(object ManagedObj)
 		{
-			if (!(ManagedObj is PRINTER_DEFAULTS pd)) throw new ArgumentException("Type of managed object must be PRINTER_DEFAULTS.");
+			if (ManagedObj is not PRINTER_DEFAULTS pd) throw new ArgumentException("Type of managed object must be PRINTER_DEFAULTS.");
 
 			var sz = IntPtr.Size * 2 + 4 + StringHelper.GetByteCount(pd.pDatatype) + (pd.pDevMode?.dmSize ?? 0);
 			var mem = new SafeCoTaskMemHandle(sz);
 			using (var str = new NativeMemoryStream(mem))
 			{
 				str.WriteReference(pd.pDatatype);
-				str.WriteReferenceObject(pd.pDevMode.HasValue ? (object)pd.pDevMode.Value : null);
+				str.WriteReferenceObject(pd.pDevMode.HasValue ? pd.pDevMode.Value : null);
 				str.Write((uint)pd.DesiredAccess);
 			}
 

PInvoke/Printing/XpsObjectModel.Factory.cs

@@ -460,7 +460,7 @@ public static partial class XpsObjectModel
 		// HRESULT CreateSolidColorBrush( const XPS_COLOR *color, IXpsOMColorProfileResource *colorProfile, IXpsOMSolidColorBrush
 		// **solidColorBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMSolidColorBrush CreateSolidColorBrush(in XPS_COLOR color, [In] IXpsOMColorProfileResource colorProfile);
+		IXpsOMSolidColorBrush CreateSolidColorBrush(in XPS_COLOR color, [In] IXpsOMColorProfileResource? colorProfile);
 
 		/// <summary>Creates an IXpsOMColorProfileResource interface, which is used to access a color profile resource stream.</summary>
 		/// <param name="acquiredStream">
@@ -643,7 +643,7 @@ public static partial class XpsObjectModel
 		// HRESULT CreateGradientStop( const XPS_COLOR *color, IXpsOMColorProfileResource *colorProfile, FLOAT offset,
 		// IXpsOMGradientStop **gradientStop );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMGradientStop CreateGradientStop(in XPS_COLOR color, [In] IXpsOMColorProfileResource colorProfile, [In] float offset);
+		IXpsOMGradientStop CreateGradientStop(in XPS_COLOR color, [In] IXpsOMColorProfileResource? colorProfile, [In] float offset);
 
 		/// <summary>Creates an IXpsOMLinearGradientBrush interface.</summary>
 		/// <param name="gradStop1">
@@ -765,24 +765,21 @@ public static partial class XpsObjectModel
 		/// <term><c>bInheritHandle</c>: a Boolean value that determines whether the returned handle can be inherited by child processes</term>
 		/// </item>
 		/// </list>
-		/// <para>If</para>
-		/// <para>lpSecurityDescriptor</para>
-		/// <para>is</para>
-		/// <para>NULL</para>
-		/// <para>, the file or device associated with the returned handle is assigned a default security descriptor.</para>
+		/// <para>
+		/// If lpSecurityDescriptor is NULL, the file or device associated with the returned handle is assigned a default security descriptor.
+		/// </para>
 		/// <para>For more information about securityAttributes, see CreateFile.</para>
 		/// </param>
 		/// <param name="flagsAndAttributes">
 		/// <para>
-		/// Specifies the settings and attributes of the file to be created. For most files, the <c>FILE_ATTRIBUTE_NORMAL</c> value can
-		/// be used.
+		/// Specifies the settings and attributes of the file to be created. For most files, the <c>FILE_ATTRIBUTE_NORMAL</c> value can be used.
 		/// </para>
 		/// <para>See CreateFile for more information about this parameter.</para>
 		/// </param>
 		/// <param name="optimizeMarkupSize">
 		/// <para>
-		/// A Boolean value that indicates whether the document markup will be optimized for size when the contents of the XPS OM are
-		/// written to the XPS package.
+		/// A Boolean value that indicates whether the document markup will be optimized for size when the contents of the XPS OM are written
+		/// to the XPS package.
 		/// </para>
 		/// <list type="table">
 		/// <listheader>
@@ -804,12 +801,11 @@ public static partial class XpsObjectModel
 		/// The IOpcPartUri interface that contains the part name of the document sequence in the new file.
 		/// </param>
 		/// <param name="coreProperties">
-		/// The IXpsOMCoreProperties interface that contains the core document properties to be given to the new file. This parameter
-		/// can be set to <c>NULL</c>.
+		/// The IXpsOMCoreProperties interface that contains the core document properties to be given to the new file. This parameter can be
+		/// set to <c>NULL</c>.
 		/// </param>
 		/// <param name="packageThumbnail">
-		/// The IXpsOMImageResource interface that contains the thumbnail image to be assigned to the new file. This parameter can be
-		/// set to <c>NULL</c>.
+		/// The IXpsOMImageResource interface that contains the thumbnail image to be assigned to the new file. This parameter can be set to <c>NULL</c>.
 		/// </param>
 		/// <param name="documentSequencePrintTicket">
 		/// The IXpsOMPrintTicketResource interface that contains the package-level print ticket to be assigned to the new file. This
@@ -821,17 +817,17 @@ public static partial class XpsObjectModel
 		/// <returns>A pointer to the new IXpsOMPackageWriter interface created by this method.</returns>
 		/// <remarks>
 		/// <para>
-		/// The file is opened and initialized and the IXpsOMPackageWriter interface that is returned is then used to write content
-		/// types, package relationships, core properties, document sequence resources, and document sequence relationships.
+		/// The file is opened and initialized and the IXpsOMPackageWriter interface that is returned is then used to write content types,
+		/// package relationships, core properties, document sequence resources, and document sequence relationships.
 		/// </para>
 		/// <para>
-		/// If documentSequencePrintTicket is set to <c>NULL</c> and the value of interleaving is <c>XPS_INTERLEAVING_ON</c>, this
-		/// method creates a blank job-level print ticket and adds a relationship to the blank print ticket. This is done to provide
-		/// more efficient streaming consumption of the package.
+		/// If documentSequencePrintTicket is set to <c>NULL</c> and the value of interleaving is <c>XPS_INTERLEAVING_ON</c>, this method
+		/// creates a blank job-level print ticket and adds a relationship to the blank print ticket. This is done to provide more efficient
+		/// streaming consumption of the package.
 		/// </para>
 		/// <para>
-		/// If documentSequencePrintTicket is set to <c>NULL</c> and the value of interleaving is <c>XPS_INTERLEAVING_OFF</c>, no blank
-		/// print ticket is created.
+		/// If documentSequencePrintTicket is set to <c>NULL</c> and the value of interleaving is <c>XPS_INTERLEAVING_OFF</c>, no blank print
+		/// ticket is created.
 		/// </para>
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomobjectfactory-createpackagewriteronfile
@@ -840,7 +836,10 @@ public static partial class XpsObjectModel
 		// *coreProperties, IXpsOMImageResource *packageThumbnail, IXpsOMPrintTicketResource *documentSequencePrintTicket, IOpcPartUri
 		// *discardControlPartName, IXpsOMPackageWriter **packageWriter );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMPackageWriter CreatePackageWriterOnFile([In, MarshalAs(UnmanagedType.LPWStr)] string fileName, [In] IntPtr securityAttributes, [In] uint flagsAndAttributes, [In] int optimizeMarkupSize, [In] XPS_INTERLEAVING interleaving, [In] IOpcPartUri documentSequencePartName, [In] IXpsOMCoreProperties coreProperties, [In] IXpsOMImageResource packageThumbnail, [In] IXpsOMPrintTicketResource documentSequencePrintTicket, [In] IOpcPartUri discardControlPartName);
+		IXpsOMPackageWriter CreatePackageWriterOnFile([In, MarshalAs(UnmanagedType.LPWStr)] string fileName, [In] SECURITY_ATTRIBUTES? securityAttributes,
+			[In] uint flagsAndAttributes, [In] int optimizeMarkupSize, [In] XPS_INTERLEAVING interleaving, [In] IOpcPartUri documentSequencePartName,
+			[In, Optional] IXpsOMCoreProperties? coreProperties, [In, Optional] IXpsOMImageResource? packageThumbnail,
+			[In, Optional] IXpsOMPrintTicketResource? documentSequencePrintTicket, [In, Optional] IOpcPartUri? discardControlPartName);
 
 		/// <summary>Opens a stream for writing the contents of an XPS OM to an XPS package.</summary>
 		/// <param name="outputStream">The stream to be used for writing.</param>
@@ -904,7 +903,9 @@ public static partial class XpsObjectModel
 		// IXpsOMPrintTicketResource *documentSequencePrintTicket, IOpcPartUri *discardControlPartName, IXpsOMPackageWriter
 		// **packageWriter );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMPackageWriter CreatePackageWriterOnStream([In] ISequentialStream outputStream, [In] int optimizeMarkupSize, [In] XPS_INTERLEAVING interleaving, [In] IOpcPartUri documentSequencePartName, [In] IXpsOMCoreProperties coreProperties, [In] IXpsOMImageResource packageThumbnail, [In] IXpsOMPrintTicketResource documentSequencePrintTicket, [In] IOpcPartUri discardControlPartName);
+		IXpsOMPackageWriter CreatePackageWriterOnStream([In] ISequentialStream outputStream, [In] int optimizeMarkupSize, [In] XPS_INTERLEAVING interleaving,
+			[In] IOpcPartUri documentSequencePartName, [In, Optional] IXpsOMCoreProperties? coreProperties, [In, Optional] IXpsOMImageResource? packageThumbnail,
+			[In, Optional] IXpsOMPrintTicketResource? documentSequencePrintTicket, [In, Optional] IOpcPartUri? discardControlPartName);
 
 		/// <summary>Creates an IOpcPartUri interface that uses the specified URI.</summary>
 		/// <param name="uri">The URI string.</param>

PInvoke/Printing/XpsObjectModel.Parts.cs

@@ -28,7 +28,7 @@ public static partial class XpsObjectModel
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.Interface)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -41,7 +41,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a pointer to the IXpsOMPackage interface that contains the core properties.</summary>
 		/// <returns>
@@ -50,7 +50,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getowner HRESULT
 		// GetOwner( IXpsOMPackage **package );
-		IXpsOMPackage GetOwner();
+		IXpsOMPackage? GetOwner();
 
 		/// <summary>Gets the <c>category</c> property.</summary>
 		/// <returns>The string that is read from the <c>category</c> property.</returns>
@@ -60,7 +60,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getcategory HRESULT
 		// GetCategory( LPWSTR *category );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetCategory();
+		string? GetCategory();
 
 		/// <summary>Sets the <c>category</c> property.</summary>
 		/// <param name="category">
@@ -69,7 +69,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>category</c> property contains a categorization of the content.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setcategory HRESULT
 		// SetCategory( LPCWSTR category );
-		void SetCategory([In, MarshalAs(UnmanagedType.LPWStr)] string category);
+		void SetCategory([In, MarshalAs(UnmanagedType.LPWStr)] string? category);
 
 		/// <summary>Gets the <c>contentStatus</c> property.</summary>
 		/// <returns>The string that is read from the <c>contentStatus</c> property.</returns>
@@ -82,7 +82,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getcontentstatus
 		// HRESULT GetContentStatus( LPWSTR *contentStatus );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetContentStatus();
+		string? GetContentStatus();
 
 		/// <summary>Sets the <c>contentStatus</c> property.</summary>
 		/// <param name="contentStatus">
@@ -94,7 +94,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setcontentstatus
 		// HRESULT SetContentStatus( LPCWSTR contentStatus );
-		void SetContentStatus([In, MarshalAs(UnmanagedType.LPWStr)] string contentStatus);
+		void SetContentStatus([In, MarshalAs(UnmanagedType.LPWStr)] string? contentStatus);
 
 		/// <summary>Gets the <c>contentType</c> property.</summary>
 		/// <returns>The string that is read from the <c>contentType</c> property.</returns>
@@ -108,7 +108,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getcontenttype
 		// HRESULT GetContentType( LPWSTR *contentType );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetContentType();
+		string? GetContentType();
 
 		/// <summary>Sets the <c>contentType</c> property.</summary>
 		/// <param name="contentType">
@@ -121,7 +121,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setcontenttype
 		// HRESULT SetContentType( LPCWSTR contentType );
-		void SetContentType([In, MarshalAs(UnmanagedType.LPWStr)] string contentType);
+		void SetContentType([In, MarshalAs(UnmanagedType.LPWStr)] string? contentType);
 
 		/// <summary>Gets the <c>created</c> property.</summary>
 		/// <returns>The date and time that are read from the <c>created</c> property.</returns>
@@ -145,7 +145,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getcreator HRESULT
 		// GetCreator( LPWSTR *creator );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetCreator();
+		string? GetCreator();
 
 		/// <summary>Sets the <c>creator</c> property.</summary>
 		/// <param name="creator">
@@ -156,7 +156,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setcreator HRESULT
 		// SetCreator( LPCWSTR creator );
-		void SetCreator([In, MarshalAs(UnmanagedType.LPWStr)] string creator);
+		void SetCreator([In, MarshalAs(UnmanagedType.LPWStr)] string? creator);
 
 		/// <summary>Gets the <c>description</c> property.</summary>
 		/// <returns>The string that is read from the <c>description</c> property.</returns>
@@ -166,7 +166,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getdescription
 		// HRESULT GetDescription( LPWSTR *description );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetDescription();
+		string? GetDescription();
 
 		/// <summary>Sets the <c>description</c> property.</summary>
 		/// <param name="description">
@@ -175,7 +175,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>description</c> property explains the content.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setdescription
 		// HRESULT SetDescription( LPCWSTR description );
-		void SetDescription([In, MarshalAs(UnmanagedType.LPWStr)] string description);
+		void SetDescription([In, MarshalAs(UnmanagedType.LPWStr)] string? description);
 
 		/// <summary>Gets the <c>identifier</c> property.</summary>
 		/// <returns>The string that is read from the <c>identifier</c> property.</returns>
@@ -187,7 +187,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getidentifier
 		// HRESULT GetIdentifier( LPWSTR *identifier );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetIdentifier();
+		string? GetIdentifier();
 
 		/// <summary>Sets the <c>identifier</c> property.</summary>
 		/// <param name="identifier">
@@ -198,7 +198,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setidentifier
 		// HRESULT SetIdentifier( LPCWSTR identifier );
-		void SetIdentifier([In, MarshalAs(UnmanagedType.LPWStr)] string identifier);
+		void SetIdentifier([In, MarshalAs(UnmanagedType.LPWStr)] string? identifier);
 
 		/// <summary>Gets the <c>keywords</c> property.</summary>
 		/// <returns>The string that is read from the <c>keywords</c> property.</returns>
@@ -211,7 +211,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getkeywords HRESULT
 		// GetKeywords( LPWSTR *keywords );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetKeywords();
+		string? GetKeywords();
 
 		/// <summary>Sets the <c>keywords</c> property.</summary>
 		/// <param name="keywords">
@@ -224,7 +224,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setkeywords HRESULT
 		// SetKeywords( LPCWSTR keywords );
-		void SetKeywords([In, MarshalAs(UnmanagedType.LPWStr)] string keywords);
+		void SetKeywords([In, MarshalAs(UnmanagedType.LPWStr)] string? keywords);
 
 		/// <summary>Gets the <c>language</c> property.</summary>
 		/// <returns>The value that is read from the <c>language</c> property.</returns>
@@ -235,7 +235,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getlanguage HRESULT
 		// GetLanguage( LPWSTR *language );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetLanguage();
+		string? GetLanguage();
 
 		/// <summary>Sets the <c>language</c> property.</summary>
 		/// <param name="language">
@@ -248,7 +248,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setlanguage HRESULT
 		// SetLanguage( LPCWSTR language );
-		void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string language);
+		void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string? language);
 
 		/// <summary>Gets the <c>lastModifiedBy</c> property.</summary>
 		/// <returns>The value that is read from the <c>lastModifiedBy</c> property.</returns>
@@ -258,7 +258,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getlastmodifiedby
 		// HRESULT GetLastModifiedBy( LPWSTR *lastModifiedBy );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetLastModifiedBy();
+		string? GetLastModifiedBy();
 
 		/// <summary>Sets the <c>lastModifiedBy</c> property.</summary>
 		/// <param name="lastModifiedBy">
@@ -268,7 +268,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>lastModifiedBy</c> property describes the user who performs the last modification.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setlastmodifiedby
 		// HRESULT SetLastModifiedBy( LPCWSTR lastModifiedBy );
-		void SetLastModifiedBy([In, MarshalAs(UnmanagedType.LPWStr)] string lastModifiedBy);
+		void SetLastModifiedBy([In, MarshalAs(UnmanagedType.LPWStr)] string? lastModifiedBy);
 
 		/// <summary>Gets the <c>lastPrinted</c> property.</summary>
 		/// <returns>The date and time that are read from the <c>lastPrinted</c> property.</returns>
@@ -284,7 +284,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>lastPrinted</c> property contains the date and time the package was last printed.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setlastprinted
 		// HRESULT SetLastPrinted( const SYSTEMTIME *lastPrinted );
-		void SetLastPrinted(in SYSTEMTIME lastPrinted);
+		void SetLastPrinted([In, Optional] PSYSTEMTIME? lastPrinted);
 
 		/// <summary>Gets the <c>modified</c> property.</summary>
 		/// <returns>The date and time that are read from the <c>modified</c> property.</returns>
@@ -300,7 +300,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>modified</c> property contains the date and time the package was last changed.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setmodified HRESULT
 		// SetModified( const SYSTEMTIME *modified );
-		void SetModified(in SYSTEMTIME modified);
+		void SetModified([In, Optional] PSYSTEMTIME? modified);
 
 		/// <summary>Gets the <c>revision</c> property.</summary>
 		/// <returns>The string that is read from the <c>revision</c> property.</returns>
@@ -310,7 +310,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getrevision HRESULT
 		// GetRevision( LPWSTR *revision );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetRevision();
+		string? GetRevision();
 
 		/// <summary>Sets the <c>revision</c> property.</summary>
 		/// <param name="revision">
@@ -319,7 +319,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>revision</c> property contains the revision number of the resource.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setrevision HRESULT
 		// SetRevision( LPCWSTR revision );
-		void SetRevision([In, MarshalAs(UnmanagedType.LPWStr)] string revision);
+		void SetRevision([In, MarshalAs(UnmanagedType.LPWStr)] string? revision);
 
 		/// <summary>Gets the <c>subject</c> property.</summary>
 		/// <returns>The string that is read from the <c>subject</c> property.</returns>
@@ -327,7 +327,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getsubject HRESULT
 		// GetSubject( LPWSTR *subject );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetSubject();
+		string? GetSubject();
 
 		/// <summary>Sets the <c>subject</c> property.</summary>
 		/// <param name="subject">
@@ -336,7 +336,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>subject</c> property contains the topic of the resource content.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setsubject HRESULT
 		// SetSubject( LPCWSTR subject );
-		void SetSubject([In, MarshalAs(UnmanagedType.LPWStr)] string subject);
+		void SetSubject([In, MarshalAs(UnmanagedType.LPWStr)] string? subject);
 
 		/// <summary>Gets the <c>title</c> property.</summary>
 		/// <returns>The string that is read from the <c>title</c> property.</returns>
@@ -344,7 +344,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-gettitle HRESULT
 		// GetTitle( LPWSTR *title );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetTitle();
+		string? GetTitle();
 
 		/// <summary>Sets the <c>title</c> property.</summary>
 		/// <param name="title">
@@ -353,7 +353,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>title</c> property contains the name given to the resource.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-settitle HRESULT
 		// SetTitle( LPCWSTR title );
-		void SetTitle([In, MarshalAs(UnmanagedType.LPWStr)] string title);
+		void SetTitle([In, MarshalAs(UnmanagedType.LPWStr)] string? title);
 
 		/// <summary>Gets the <c>version</c> property.</summary>
 		/// <returns>The string that is read from the <c>version</c> property.</returns>
@@ -361,7 +361,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-getversion HRESULT
 		// GetVersion( LPWSTR *version );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetVersion();
+		string? GetVersion();
 
 		/// <summary>Sets the <c>version</c> property.</summary>
 		/// <param name="version">
@@ -370,7 +370,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The <c>version</c> property contains the version number of the resource.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcoreproperties-setversion HRESULT
 		// SetVersion( LPCWSTR version );
-		void SetVersion([In, MarshalAs(UnmanagedType.LPWStr)] string version);
+		void SetVersion([In, MarshalAs(UnmanagedType.LPWStr)] string? version);
 
 		/// <summary>Makes a deep copy of the interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>
@@ -397,7 +397,7 @@ public static partial class XpsObjectModel
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.Interface)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -410,7 +410,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a pointer to the IXpsOMDocumentSequence interface that contains the document.</summary>
 		/// <returns>
@@ -606,7 +606,7 @@ public static partial class XpsObjectModel
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.Interface)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -619,7 +619,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a pointer to the IXpsOMPackage interface that contains the document sequence.</summary>
 		/// <returns>
@@ -628,7 +628,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomdocumentsequence-getowner HRESULT
 		// GetOwner( IXpsOMPackage **package );
-		IXpsOMPackage GetOwner();
+		IXpsOMPackage? GetOwner();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMDocumentCollection interface, which contains the documents specified in the document sequence.
@@ -659,7 +659,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomdocumentsequence-getprintticketresource
 		// HRESULT GetPrintTicketResource( IXpsOMPrintTicketResource **printTicketResource );
-		IXpsOMPrintTicketResource GetPrintTicketResource();
+		IXpsOMPrintTicketResource? GetPrintTicketResource();
 
 		/// <summary>Sets the job-level print ticket resource for the document sequence.</summary>
 		/// <param name="printTicketResource">
@@ -672,7 +672,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomdocumentsequence-setprintticketresource
 		// HRESULT SetPrintTicketResource( IXpsOMPrintTicketResource *printTicketResource );
-		void SetPrintTicketResource([In] IXpsOMPrintTicketResource printTicketResource);
+		void SetPrintTicketResource([In] IXpsOMPrintTicketResource? printTicketResource);
 	}
 
 	/// <summary>
@@ -698,7 +698,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-getdocumentsequence HRESULT
 		// GetDocumentSequence( IXpsOMDocumentSequence **documentSequence );
-		IXpsOMDocumentSequence GetDocumentSequence();
+		IXpsOMDocumentSequence? GetDocumentSequence();
 
 		/// <summary>Sets the IXpsOMDocumentSequence interface of the XPS package.</summary>
 		/// <param name="documentSequence">
@@ -706,7 +706,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-setdocumentsequence HRESULT
 		// SetDocumentSequence( IXpsOMDocumentSequence *documentSequence );
-		void SetDocumentSequence([In] IXpsOMDocumentSequence documentSequence);
+		void SetDocumentSequence([In] IXpsOMDocumentSequence? documentSequence);
 
 		/// <summary>Gets a pointer to the IXpsOMCoreProperties interface of the XPS package.</summary>
 		/// <returns>
@@ -715,7 +715,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-getcoreproperties HRESULT
 		// GetCoreProperties( IXpsOMCoreProperties **coreProperties );
-		IXpsOMCoreProperties GetCoreProperties();
+		IXpsOMCoreProperties? GetCoreProperties();
 
 		/// <summary>Sets the IXpsOMCoreProperties interface of the XPS package.</summary>
 		/// <param name="coreProperties">
@@ -724,7 +724,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-setcoreproperties HRESULT
 		// SetCoreProperties( IXpsOMCoreProperties *coreProperties );
-		void SetCoreProperties([In] IXpsOMCoreProperties coreProperties);
+		void SetCoreProperties([In] IXpsOMCoreProperties? coreProperties);
 
 		/// <summary>Gets the name of the discard control part in the XPS package.</summary>
 		/// <returns>
@@ -733,7 +733,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-getdiscardcontrolpartname
 		// HRESULT GetDiscardControlPartName( IOpcPartUri **discardControlPartUri );
-		IOpcPartUri GetDiscardControlPartName();
+		IOpcPartUri? GetDiscardControlPartName();
 
 		/// <summary>Sets the name of the discard control part in the XPS package.</summary>
 		/// <param name="discardControlPartUri">
@@ -742,7 +742,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-setdiscardcontrolpartname
 		// HRESULT SetDiscardControlPartName( IOpcPartUri *discardControlPartUri );
-		void SetDiscardControlPartName([In] IOpcPartUri discardControlPartUri);
+		void SetDiscardControlPartName([In] IOpcPartUri? discardControlPartUri);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMImageResource interface of the thumbnail resource that is associated with the XPS package.
@@ -757,7 +757,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-getthumbnailresource
 		// HRESULT GetThumbnailResource( IXpsOMImageResource **imageResource );
-		IXpsOMImageResource GetThumbnailResource();
+		IXpsOMImageResource? GetThumbnailResource();
 
 		/// <summary>Sets the thumbnail image of the XPS document.</summary>
 		/// <param name="imageResource">
@@ -770,7 +770,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-setthumbnailresource
 		// HRESULT SetThumbnailResource( IXpsOMImageResource *imageResource );
-		void SetThumbnailResource([In] IXpsOMImageResource imageResource);
+		void SetThumbnailResource([In] IXpsOMImageResource? imageResource);
 
 		/// <summary>Writes the XPS package to a specified file.</summary>
 		/// <param name="fileName">The name of the file to be created. This parameter must not be <c>NULL</c>.</param>
@@ -827,7 +827,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompackage-writetofile HRESULT
 		// WriteToFile( LPCWSTR fileName, LPSECURITY_ATTRIBUTES securityAttributes, DWORD flagsAndAttributes, BOOL optimizeMarkupSize );
-		void WriteToFile([In, MarshalAs(UnmanagedType.LPWStr)] string fileName, [In] SECURITY_ATTRIBUTES securityAttributes, [In] FileFlagsAndAttributes flagsAndAttributes, [In, MarshalAs(UnmanagedType.Bool)] bool optimizeMarkupSize);
+		void WriteToFile([In, MarshalAs(UnmanagedType.LPWStr)] string fileName, [In] SECURITY_ATTRIBUTES? securityAttributes, [In] FileFlagsAndAttributes flagsAndAttributes, [In, MarshalAs(UnmanagedType.Bool)] bool optimizeMarkupSize);
 
 		/// <summary>Writes the XPS package to a specified stream.</summary>
 		/// <param name="stream">The stream that receives the serialized contents of the package. This parameter must not be <c>NULL</c>.</param>
@@ -931,8 +931,9 @@ public static partial class XpsObjectModel
 		// IXpsOMDocumentStructureResource *documentStructure, IXpsOMSignatureBlockResourceCollection *signatureBlockResources,
 		// IXpsOMPartUriCollection *restrictedFonts );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void StartNewDocument([In] IOpcPartUri documentPartName, [In] IXpsOMPrintTicketResource documentPrintTicket, [In] IXpsOMDocumentStructureResource documentStructure,
-			[In] IXpsOMSignatureBlockResourceCollection signatureBlockResources, [In] IXpsOMPartUriCollection restrictedFonts);
+		void StartNewDocument([In] IOpcPartUri documentPartName, [In, Optional] IXpsOMPrintTicketResource? documentPrintTicket,
+			[In, Optional] IXpsOMDocumentStructureResource? documentStructure,
+			[In, Optional] IXpsOMSignatureBlockResourceCollection? signatureBlockResources, [In, Optional] IXpsOMPartUriCollection? restrictedFonts);
 
 		/// <summary>Writes a new FixedPage part to the currently open FixedDocument part in the package.</summary>
 		/// <param name="page">
@@ -974,8 +975,8 @@ public static partial class XpsObjectModel
 		// AddPage( IXpsOMPage *page, const XPS_SIZE *advisoryPageDimensions, IXpsOMPartUriCollection *discardableResourceParts,
 		// IXpsOMStoryFragmentsResource *storyFragments, IXpsOMPrintTicketResource *pagePrintTicket, IXpsOMImageResource *pageThumbnail );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void AddPage([In] IXpsOMPage page, in XPS_SIZE advisoryPageDimensions, [In] IXpsOMPartUriCollection discardableResourceParts,
-			[In] IXpsOMStoryFragmentsResource storyFragments, [In] IXpsOMPrintTicketResource pagePrintTicket, [In] IXpsOMImageResource pageThumbnail);
+		void AddPage([In] IXpsOMPage page, in XPS_SIZE advisoryPageDimensions, [In, Optional] IXpsOMPartUriCollection? discardableResourceParts,
+			[In, Optional] IXpsOMStoryFragmentsResource? storyFragments, [In] IXpsOMPrintTicketResource? pagePrintTicket, [In, Optional] IXpsOMImageResource? pageThumbnail);
 
 		/// <summary>Creates a new part resource in the package.</summary>
 		/// <param name="resource">
@@ -1104,7 +1105,7 @@ public static partial class XpsObjectModel
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.Interface)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -1117,7 +1118,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a pointer to the IXpsOMPageReference interface that contains the page.</summary>
 		/// <returns>A pointer to the IXpsOMPageReference interface that contains the page.</returns>
@@ -1125,7 +1126,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-getowner HRESULT GetOwner(
 		// IXpsOMPageReference **pageReference );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMPageReference GetOwner();
+		IXpsOMPageReference? GetOwner();
 
 		/// <summary>Gets a pointer to an IXpsOMVisualCollection interface that contains a collection of the page's visual objects.</summary>
 		/// <returns>A pointer to the IXpsOMVisualCollection interface that contains a collection of the page's visual objects.</returns>
@@ -1295,7 +1296,7 @@ public static partial class XpsObjectModel
 		// GetLanguage( LPWSTR *language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetLanguage();
+		string? GetLanguage();
 
 		/// <summary>Sets the <c>Language</c> property of the page.</summary>
 		/// <param name="language">
@@ -1308,7 +1309,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-setlanguage HRESULT
 		// SetLanguage( LPCWSTR language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string language);
+		void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string? language);
 
 		/// <summary>Gets the <c>Name</c> property of the page.</summary>
 		/// <returns>
@@ -1318,7 +1319,7 @@ public static partial class XpsObjectModel
 		// LPWSTR *name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetName();
+		string? GetName();
 
 		/// <summary>Sets the <c>Name</c> property of this page.</summary>
 		/// <param name="name">
@@ -1332,7 +1333,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-setname HRESULT SetName(
 		// LPCWSTR name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string name);
+		void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string? name);
 
 		/// <summary>Gets a Boolean value that indicates whether the page is the target of a hyperlink.</summary>
 		/// <returns>
@@ -1424,7 +1425,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-getdictionary HRESULT
 		// GetDictionary( IXpsOMDictionary **resourceDictionary );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMDictionary GetDictionary();
+		IXpsOMDictionary? GetDictionary();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMDictionary interface of the local, unshared dictionary that is associated with this page.
@@ -1457,7 +1458,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-getdictionarylocal HRESULT
 		// GetDictionaryLocal( IXpsOMDictionary **resourceDictionary );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMDictionary GetDictionaryLocal();
+		IXpsOMDictionary? GetDictionaryLocal();
 
 		/// <summary>Sets the IXpsOMDictionary interface pointer of the page's local dictionary resource.</summary>
 		/// <param name="resourceDictionary">
@@ -1499,7 +1500,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-setdictionarylocal HRESULT
 		// SetDictionaryLocal( IXpsOMDictionary *resourceDictionary );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetDictionaryLocal([In] IXpsOMDictionary resourceDictionary);
+		void SetDictionaryLocal([In] IXpsOMDictionary? resourceDictionary);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMRemoteDictionaryResource interface of the shared dictionary resource that is used by this page.
@@ -1535,7 +1536,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-getdictionaryresource HRESULT
 		// GetDictionaryResource( IXpsOMRemoteDictionaryResource **remoteDictionaryResource );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMRemoteDictionaryResource GetDictionaryResource();
+		IXpsOMRemoteDictionaryResource? GetDictionaryResource();
 
 		/// <summary>Sets the IXpsOMRemoteDictionaryResource interface pointer of the page's remote dictionary resource.</summary>
 		/// <param name="remoteDictionaryResource">
@@ -1574,7 +1575,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompage-setdictionaryresource HRESULT
 		// SetDictionaryResource( IXpsOMRemoteDictionaryResource *remoteDictionaryResource );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetDictionaryResource([In] IXpsOMRemoteDictionaryResource remoteDictionaryResource);
+		void SetDictionaryResource([In] IXpsOMRemoteDictionaryResource? remoteDictionaryResource);
 
 		/// <summary>Writes the page to the specified stream.</summary>
 		/// <param name="stream">The stream that receives the serialized contents of the page.</param>
@@ -1712,7 +1713,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-getowner HRESULT
 		// GetOwner( IXpsOMDocument **document );
-		IXpsOMDocument GetOwner();
+		IXpsOMDocument? GetOwner();
 
 		/// <summary>Gets a pointer to the IXpsOMPage interface that contains the page.</summary>
 		/// <returns>A pointer to the IXpsOMPage interface of the page. If a page has not been set, a <c>NULL</c> pointer is returned.</returns>
@@ -1730,7 +1731,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-getpage HRESULT
 		// GetPage( IXpsOMPage **page );
-		IXpsOMPage GetPage();
+		IXpsOMPage? GetPage();
 
 		/// <summary>Sets the IXpsOMPage interface of the page reference.</summary>
 		/// <param name="page">The IXpsOMPage interface pointer of the page.</param>
@@ -1849,7 +1850,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-getstoryfragmentsresource
 		// HRESULT GetStoryFragmentsResource( IXpsOMStoryFragmentsResource **storyFragmentsResource );
-		IXpsOMStoryFragmentsResource GetStoryFragmentsResource();
+		IXpsOMStoryFragmentsResource? GetStoryFragmentsResource();
 
 		/// <summary>
 		/// Sets the IXpsOMStoryFragmentsResource interface pointer of the StoryFragments resource to be assigned to the page.
@@ -1868,7 +1869,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-setstoryfragmentsresource
 		// HRESULT SetStoryFragmentsResource( IXpsOMStoryFragmentsResource *storyFragmentsResource );
-		void SetStoryFragmentsResource([In] IXpsOMStoryFragmentsResource storyFragmentsResource);
+		void SetStoryFragmentsResource([In] IXpsOMStoryFragmentsResource? storyFragmentsResource);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMPrintTicketResource interface of the page-level print ticket resource that is associated with
@@ -1884,7 +1885,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-getprintticketresource
 		// HRESULT GetPrintTicketResource( IXpsOMPrintTicketResource **printTicketResource );
-		IXpsOMPrintTicketResource GetPrintTicketResource();
+		IXpsOMPrintTicketResource? GetPrintTicketResource();
 
 		/// <summary>
 		/// Sets the IXpsOMPrintTicketResource interface pointer of the page-level print ticket resource that is to be assigned to the page.
@@ -1895,7 +1896,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-setprintticketresource
 		// HRESULT SetPrintTicketResource( IXpsOMPrintTicketResource *printTicketResource );
-		void SetPrintTicketResource([In] IXpsOMPrintTicketResource printTicketResource);
+		void SetPrintTicketResource([In] IXpsOMPrintTicketResource? printTicketResource);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMImageResource interface of the thumbnail image resource that is associated with the page.
@@ -1913,7 +1914,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-getthumbnailresource
 		// HRESULT GetThumbnailResource( IXpsOMImageResource **imageResource );
-		IXpsOMImageResource GetThumbnailResource();
+		IXpsOMImageResource? GetThumbnailResource();
 
 		/// <summary>
 		/// Sets the pointer to the IXpsOMImageResource interface of the thumbnail image resource to be assigned to the page.
@@ -1928,7 +1929,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompagereference-setthumbnailresource
 		// HRESULT SetThumbnailResource( IXpsOMImageResource *imageResource );
-		void SetThumbnailResource([In] IXpsOMImageResource imageResource);
+		void SetThumbnailResource([In] IXpsOMImageResource? imageResource);
 
 		/// <summary>
 		/// Gets an IXpsOMNameCollection interface that contains the names of all the document subtree objects whose
@@ -2124,7 +2125,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IOpcPartUri GetPartName();
+		IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -2137,7 +2138,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetPartName([In] IOpcPartUri partUri);
+		void SetPartName([In] IOpcPartUri? partUri);
 	}
 
 	/// <summary>Provides access to all shared, part-based resources of the XPS document.</summary>

PInvoke/Printing/XpsObjectModel.cs

@@ -1,5 +1,8 @@
-using System.Runtime.CompilerServices;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices.ComTypes;
+using Vanara.Collections;
+using Vanara.Extensions.Reflection;
 using static Vanara.PInvoke.Opc;
 using static Vanara.PInvoke.UrlMon;
 
@@ -106,7 +109,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMMatrixTransform GetTransform();
+		new IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared, resolved matrix transform for the visual.
@@ -139,7 +142,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMMatrixTransform GetTransformLocal();
+		new IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the local, unshared matrix transform.</summary>
 		/// <param name="matrixTransform">
@@ -184,7 +187,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetTransformLocal([In] IXpsOMMatrixTransform matrixTransform);
+		new void SetTransformLocal([In] IXpsOMMatrixTransform? matrixTransform);
 
 		/// <summary>
 		/// Gets the lookup key name of the IXpsOMMatrixTransform interface in a resource dictionary that contains the resolved matrix
@@ -219,7 +222,7 @@ public static partial class XpsObjectModel
 		// GetTransformLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetTransformLookup();
+		new string? GetTransformLookup();
 
 		/// <summary>Sets the lookup key name of a shared matrix transform in a resource dictionary.</summary>
 		/// <param name="key">The lookup key name of the matrix transform in the dictionary.</param>
@@ -262,7 +265,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlookup HRESULT
 		// SetTransformLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the resolved geometry of the visual's clipping region.
@@ -298,7 +301,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometry HRESULT
 		// GetClipGeometry( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMGeometry GetClipGeometry();
+		new IXpsOMGeometry? GetClipGeometry();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the local, unshared geometry of the visual's clipping region.
@@ -330,7 +333,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometrylocal HRESULT
 		// GetClipGeometryLocal( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMGeometry GetClipGeometryLocal();
+		new IXpsOMGeometry? GetClipGeometryLocal();
 
 		/// <summary>Sets the local, unshared clipping region for the visual.</summary>
 		/// <param name="clipGeometry">
@@ -376,7 +379,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylocal HRESULT
 		// SetClipGeometryLocal( IXpsOMGeometry *clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetClipGeometryLocal([In] IXpsOMGeometry clipGeometry);
+		new void SetClipGeometryLocal([In] IXpsOMGeometry? clipGeometry);
 
 		/// <summary>
 		/// Gets the lookup key for the IXpsOMGeometry interface in a resource dictionary that contains the visual's clipping region.
@@ -409,7 +412,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetClipGeometryLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetClipGeometryLookup();
+		new string? GetClipGeometryLookup();
 
 		/// <summary>Sets the lookup key name of a shared clip geometry in a resource dictionary.</summary>
 		/// <param name="key">
@@ -454,7 +457,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylookup
 		// HRESULT SetClipGeometryLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the opacity value of this visual.</summary>
 		/// <returns>The opacity value.</returns>
@@ -508,7 +511,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrush HRESULT
 		// GetOpacityMaskBrush( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMBrush GetOpacityMaskBrush();
+		new IXpsOMBrush? GetOpacityMaskBrush();
 
 		/// <summary>Gets the local, unshared opacity mask brush for the visual.</summary>
 		/// <returns>
@@ -538,7 +541,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrushlocal
 		// HRESULT GetOpacityMaskBrushLocal( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMBrush GetOpacityMaskBrushLocal();
+		new IXpsOMBrush? GetOpacityMaskBrushLocal();
 
 		/// <summary>Sets the IXpsOMBrush interface pointer as the local, unshared opacity mask brush.</summary>
 		/// <param name="opacityMaskBrush">
@@ -584,7 +587,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlocal
 		// HRESULT SetOpacityMaskBrushLocal( IXpsOMBrush *opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetOpacityMaskBrushLocal([In] IXpsOMBrush opacityMaskBrush);
+		new void SetOpacityMaskBrushLocal([In] IXpsOMBrush? opacityMaskBrush);
 
 		/// <summary>Gets the name of the lookup key of the shared opacity mask brush in a resource dictionary.</summary>
 		/// <returns>
@@ -615,7 +618,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetOpacityMaskBrushLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetOpacityMaskBrushLookup();
+		new string? GetOpacityMaskBrushLookup();
 
 		/// <summary>Sets the lookup key name of a shared opacity mask brush in a resource dictionary.</summary>
 		/// <param name="key">
@@ -660,7 +663,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlookup
 		// HRESULT SetOpacityMaskBrushLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the <c>Name</c> property of the visual.</summary>
 		/// <returns>The <c>Name</c> property string. If the <c>Name</c> property has not been set, a <c>NULL</c> pointer is returned.</returns>
@@ -668,7 +671,7 @@ public static partial class XpsObjectModel
 		// LPWSTR *name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetName();
+		new string? GetName();
 
 		/// <summary>Sets the <c>Name</c> property of the visual.</summary>
 		/// <param name="name">The name of the visual. A <c>NULL</c> pointer clears the <c>Name</c> property.</param>
@@ -681,7 +684,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setname HRESULT SetName(
 		// LPCWSTR name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string name);
+		new void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string? name);
 
 		/// <summary>Gets a value that indicates whether the visual is the target of a hyperlink.</summary>
 		/// <returns>
@@ -739,7 +742,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gethyperlinknavigateuri
 		// HRESULT GetHyperlinkNavigateUri( IUri **hyperlinkUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IUri GetHyperlinkNavigateUri();
+		new IUri? GetHyperlinkNavigateUri();
 
 		/// <summary>Sets the destination URI of the visual's hyperlink.</summary>
 		/// <param name="hyperlinkUri">The IUri interface that contains the destination URI of the visual's hyperlink.</param>
@@ -750,7 +753,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-sethyperlinknavigateuri
 		// HRESULT SetHyperlinkNavigateUri( IUri *hyperlinkUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetHyperlinkNavigateUri([In] IUri hyperlinkUri);
+		new void SetHyperlinkNavigateUri([In] IUri? hyperlinkUri);
 
 		/// <summary>Gets the <c>Language</c> property of the visual and of its contents.</summary>
 		/// <returns>
@@ -764,7 +767,7 @@ public static partial class XpsObjectModel
 		// GetLanguage( LPWSTR *language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetLanguage();
+		new string? GetLanguage();
 
 		/// <summary>Sets the <c>Language</c> property of the visual.</summary>
 		/// <param name="language">
@@ -777,7 +780,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setlanguage HRESULT
 		// SetLanguage( LPCWSTR language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string language);
+		new void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string? language);
 
 		/// <summary>
 		/// Gets a pointer to an IXpsOMVisualCollection interface that contains a collection of the visual objects in the canvas.
@@ -877,7 +880,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-getaccessibilityshortdescription
 		// HRESULT GetAccessibilityShortDescription( LPWSTR *shortDescription );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetAccessibilityShortDescription();
+		string? GetAccessibilityShortDescription();
 
 		/// <summary>
 		/// Sets the short textual description of the object's contents. This text is used by accessibility clients to describe the object.
@@ -891,7 +894,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-setaccessibilityshortdescription
 		// HRESULT SetAccessibilityShortDescription( LPCWSTR shortDescription );
-		void SetAccessibilityShortDescription([In, MarshalAs(UnmanagedType.LPWStr)] string shortDescription);
+		void SetAccessibilityShortDescription([In, MarshalAs(UnmanagedType.LPWStr)] string? shortDescription);
 
 		/// <summary>
 		/// Gets the long (detailed) textual description of the object's contents. This text is used by accessibility clients to
@@ -910,7 +913,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-getaccessibilitylongdescription
 		// HRESULT GetAccessibilityLongDescription( LPWSTR *longDescription );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetAccessibilityLongDescription();
+		string? GetAccessibilityLongDescription();
 
 		/// <summary>
 		/// Sets the long (detailed) textual description of the object's contents. This text is used by accessibility clients to
@@ -925,7 +928,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-setaccessibilitylongdescription
 		// HRESULT SetAccessibilityLongDescription( LPCWSTR longDescription );
-		void SetAccessibilityLongDescription([In, MarshalAs(UnmanagedType.LPWStr)] string longDescription);
+		void SetAccessibilityLongDescription([In, MarshalAs(UnmanagedType.LPWStr)] string? longDescription);
 
 		/// <summary>Gets a pointer to the resolved IXpsOMDictionary interface of the dictionary associated with the canvas.</summary>
 		/// <returns>
@@ -962,7 +965,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-getdictionary HRESULT
 		// GetDictionary( IXpsOMDictionary **resourceDictionary );
-		IXpsOMDictionary GetDictionary();
+		IXpsOMDictionary? GetDictionary();
 
 		/// <summary>Gets a pointer to the IXpsOMDictionary interface of the local, unshared dictionary.</summary>
 		/// <returns>
@@ -998,7 +1001,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-getdictionarylocal HRESULT
 		// GetDictionaryLocal( IXpsOMDictionary **resourceDictionary );
-		IXpsOMDictionary GetDictionaryLocal();
+		IXpsOMDictionary? GetDictionaryLocal();
 
 		/// <summary>Sets the IXpsOMDictionary interface pointer of the local, unshared dictionary.</summary>
 		/// <param name="resourceDictionary">
@@ -1040,7 +1043,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-setdictionarylocal HRESULT
 		// SetDictionaryLocal( IXpsOMDictionary *resourceDictionary );
-		void SetDictionaryLocal([In] IXpsOMDictionary resourceDictionary);
+		void SetDictionaryLocal([In] IXpsOMDictionary? resourceDictionary);
 
 		/// <summary>Gets a pointer to the IXpsOMRemoteDictionaryResource interface of the remote dictionary resource.</summary>
 		/// <returns>
@@ -1073,7 +1076,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-getdictionaryresource
 		// HRESULT GetDictionaryResource( IXpsOMRemoteDictionaryResource **remoteDictionaryResource );
-		IXpsOMRemoteDictionaryResource GetDictionaryResource();
+		IXpsOMRemoteDictionaryResource? GetDictionaryResource();
 
 		/// <summary>Sets the IXpsOMRemoteDictionaryResource interface pointer of the remote dictionary resource.</summary>
 		/// <param name="remoteDictionaryResource">
@@ -1111,7 +1114,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcanvas-setdictionaryresource
 		// HRESULT SetDictionaryResource( IXpsOMRemoteDictionaryResource *remoteDictionaryResource );
-		void SetDictionaryResource([In] IXpsOMRemoteDictionaryResource remoteDictionaryResource);
+		void SetDictionaryResource([In] IXpsOMRemoteDictionaryResource? remoteDictionaryResource);
 
 		/// <summary>Makes a deep copy of the interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>
@@ -1136,7 +1139,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -1149,7 +1152,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a new, read-only copy of the stream that is associated with this resource.</summary>
 		/// <returns>A new, read-only copy of the stream that is associated with this resource.</returns>
@@ -1209,7 +1212,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcolorprofileresourcecollection-getat
 		// HRESULT GetAt( UINT32 index, IXpsOMColorProfileResource **object );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMColorProfileResource GetAt([In] uint index);
+		IXpsOMColorProfileResource? GetAt([In] uint index);
 
 		/// <summary>Inserts an IXpsOMColorProfileResource interface pointer at a specified location in the collection.</summary>
 		/// <param name="index">
@@ -1282,7 +1285,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomcolorprofileresourcecollection-getbypartname
 		// HRESULT GetByPartName( IOpcPartUri *partName, IXpsOMColorProfileResource **part );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMColorProfileResource GetByPartName([In] IOpcPartUri partName);
+		IXpsOMColorProfileResource? GetByPartName([In] IOpcPartUri partName);
 	}
 
 	/// <summary>A collection of XPS_DASH structures.</summary>
@@ -1414,7 +1417,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomdictionary-getbykey HRESULT
 		// GetByKey( LPCWSTR key, IXpsOMShareable *beforeEntry, IXpsOMShareable **entry );
-		IXpsOMShareable GetByKey([In, MarshalAs(UnmanagedType.LPWStr)] string key, [In] IXpsOMShareable beforeEntry);
+		IXpsOMShareable GetByKey([In, MarshalAs(UnmanagedType.LPWStr)] string key, [In] IXpsOMShareable? beforeEntry);
 
 		/// <summary>Gets the index of an IXpsOMShareable interface from the dictionary.</summary>
 		/// <param name="entry">The IXpsOMShareable interface pointer to be found in the dictionary.</param>
@@ -1556,7 +1559,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -1578,7 +1581,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomdocumentstructureresource-getowner
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMDocument GetOwner();
+		IXpsOMDocument? GetOwner();
 
 		/// <summary>Gets a new, read-only copy of the stream that is associated with this resource.</summary>
 		/// <returns>A new, read-only copy of the stream that is associated with this resource.</returns>
@@ -1633,7 +1636,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -1836,7 +1839,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomfontresourcecollection-getbypartname
 		// HRESULT GetByPartName( IOpcPartUri *partName, IXpsOMFontResource **part );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMFontResource GetByPartName([In] IOpcPartUri partName);
+		IXpsOMFontResource? GetByPartName([In] IOpcPartUri partName);
 	}
 
 	/// <summary>Describes the shape of a path or of a clipping region.</summary>
@@ -1923,7 +1926,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometry-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **transform );
-		IXpsOMMatrixTransform GetTransform();
+		IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared matrix transform for the geometry.
@@ -1955,7 +1958,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometry-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **transform );
-		IXpsOMMatrixTransform GetTransformLocal();
+		IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the local, unshared matrix transform.</summary>
 		/// <param name="transform">
@@ -1998,7 +2001,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometry-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *transform );
-		void SetTransformLocal([In] IXpsOMMatrixTransform transform);
+		void SetTransformLocal([In] IXpsOMMatrixTransform? transform);
 
 		/// <summary>
 		/// Gets the lookup key for the IXpsOMMatrixTransform interface that contains the resolved matrix transform for the geometry.
@@ -2032,7 +2035,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometry-gettransformlookup HRESULT
 		// GetTransformLookup( LPWSTR *lookup );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetTransformLookup();
+		string? GetTransformLookup();
 
 		/// <summary>Sets the lookup key name of a shared matrix transform in a resource dictionary.</summary>
 		/// <param name="lookup">The key name of the shared matrix transform in the resource dictionary.</param>
@@ -2073,7 +2076,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometry-settransformlookup HRESULT
 		// SetTransformLookup( LPCWSTR lookup );
-		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string lookup);
+		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? lookup);
 
 		/// <summary>Makes a deep copy of the interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>
@@ -2099,7 +2102,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometryfigure-getowner HRESULT
 		// GetOwner( IXpsOMGeometry **owner );
-		IXpsOMGeometry GetOwner();
+		IXpsOMGeometry? GetOwner();
 
 		/// <summary>Gets the segment data points for the geometry figure.</summary>
 		/// <param name="dataCount">
@@ -2232,7 +2235,7 @@ public static partial class XpsObjectModel
 		/// <remarks>For an example of how to use this method in a program, see the code example in GetSegmentData.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometryfigure-getsegmenttypes
 		// HRESULT GetSegmentTypes( UINT32 *segmentCount, XPS_SEGMENT_TYPE *segmentTypes );
-		void GetSegmentTypes([In, Out] ref uint segmentCount, [In, Out] XPS_SEGMENT_TYPE[] segmentTypes);
+		void GetSegmentTypes([In, Out] ref uint segmentCount, [In, Out] XPS_SEGMENT_TYPE[]? segmentTypes);
 
 		/// <summary>Gets stroke definitions for the figure's segments.</summary>
 		/// <param name="segmentCount">
@@ -2276,7 +2279,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgeometryfigure-getsegmentstrokes
 		// HRESULT GetSegmentStrokes( UINT32 *segmentCount, BOOL *segmentStrokes );
-		void GetSegmentStrokes([In, Out] ref uint segmentCount, [In, Out, MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.Bool)] bool[] segmentStrokes);
+		void GetSegmentStrokes([In, Out] ref uint segmentCount, [In, Out, MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.Bool)] bool[]? segmentStrokes);
 
 		/// <summary>Sets the segment information and data points for segments in the figure.</summary>
 		/// <param name="segmentCount">
@@ -2672,7 +2675,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMMatrixTransform GetTransform();
+		new IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared, resolved matrix transform for the visual.
@@ -2705,7 +2708,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMMatrixTransform GetTransformLocal();
+		new IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the local, unshared matrix transform.</summary>
 		/// <param name="matrixTransform">
@@ -2750,7 +2753,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetTransformLocal([In] IXpsOMMatrixTransform matrixTransform);
+		new void SetTransformLocal([In] IXpsOMMatrixTransform? matrixTransform);
 
 		/// <summary>
 		/// Gets the lookup key name of the IXpsOMMatrixTransform interface in a resource dictionary that contains the resolved matrix
@@ -2785,7 +2788,7 @@ public static partial class XpsObjectModel
 		// GetTransformLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetTransformLookup();
+		new string? GetTransformLookup();
 
 		/// <summary>Sets the lookup key name of a shared matrix transform in a resource dictionary.</summary>
 		/// <param name="key">The lookup key name of the matrix transform in the dictionary.</param>
@@ -2828,7 +2831,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlookup HRESULT
 		// SetTransformLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the resolved geometry of the visual's clipping region.
@@ -2864,7 +2867,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometry HRESULT
 		// GetClipGeometry( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMGeometry GetClipGeometry();
+		new IXpsOMGeometry? GetClipGeometry();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the local, unshared geometry of the visual's clipping region.
@@ -2896,7 +2899,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometrylocal HRESULT
 		// GetClipGeometryLocal( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMGeometry GetClipGeometryLocal();
+		new IXpsOMGeometry? GetClipGeometryLocal();
 
 		/// <summary>Sets the local, unshared clipping region for the visual.</summary>
 		/// <param name="clipGeometry">
@@ -2942,7 +2945,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylocal HRESULT
 		// SetClipGeometryLocal( IXpsOMGeometry *clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetClipGeometryLocal([In] IXpsOMGeometry clipGeometry);
+		new void SetClipGeometryLocal([In] IXpsOMGeometry? clipGeometry);
 
 		/// <summary>
 		/// Gets the lookup key for the IXpsOMGeometry interface in a resource dictionary that contains the visual's clipping region.
@@ -2975,7 +2978,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetClipGeometryLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetClipGeometryLookup();
+		new string? GetClipGeometryLookup();
 
 		/// <summary>Sets the lookup key name of a shared clip geometry in a resource dictionary.</summary>
 		/// <param name="key">
@@ -3020,7 +3023,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylookup
 		// HRESULT SetClipGeometryLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the opacity value of this visual.</summary>
 		/// <returns>The opacity value.</returns>
@@ -3074,7 +3077,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrush HRESULT
 		// GetOpacityMaskBrush( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMBrush GetOpacityMaskBrush();
+		new IXpsOMBrush? GetOpacityMaskBrush();
 
 		/// <summary>Gets the local, unshared opacity mask brush for the visual.</summary>
 		/// <returns>
@@ -3104,7 +3107,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrushlocal
 		// HRESULT GetOpacityMaskBrushLocal( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMBrush GetOpacityMaskBrushLocal();
+		new IXpsOMBrush? GetOpacityMaskBrushLocal();
 
 		/// <summary>Sets the IXpsOMBrush interface pointer as the local, unshared opacity mask brush.</summary>
 		/// <param name="opacityMaskBrush">
@@ -3150,7 +3153,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlocal
 		// HRESULT SetOpacityMaskBrushLocal( IXpsOMBrush *opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetOpacityMaskBrushLocal([In] IXpsOMBrush opacityMaskBrush);
+		new void SetOpacityMaskBrushLocal([In] IXpsOMBrush? opacityMaskBrush);
 
 		/// <summary>Gets the name of the lookup key of the shared opacity mask brush in a resource dictionary.</summary>
 		/// <returns>
@@ -3181,7 +3184,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetOpacityMaskBrushLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetOpacityMaskBrushLookup();
+		new string? GetOpacityMaskBrushLookup();
 
 		/// <summary>Sets the lookup key name of a shared opacity mask brush in a resource dictionary.</summary>
 		/// <param name="key">
@@ -3226,7 +3229,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlookup
 		// HRESULT SetOpacityMaskBrushLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the <c>Name</c> property of the visual.</summary>
 		/// <returns>The <c>Name</c> property string. If the <c>Name</c> property has not been set, a <c>NULL</c> pointer is returned.</returns>
@@ -3234,7 +3237,7 @@ public static partial class XpsObjectModel
 		// LPWSTR *name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetName();
+		new string? GetName();
 
 		/// <summary>Sets the <c>Name</c> property of the visual.</summary>
 		/// <param name="name">The name of the visual. A <c>NULL</c> pointer clears the <c>Name</c> property.</param>
@@ -3247,7 +3250,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setname HRESULT SetName(
 		// LPCWSTR name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string name);
+		new void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string? name);
 
 		/// <summary>Gets a value that indicates whether the visual is the target of a hyperlink.</summary>
 		/// <returns>
@@ -3305,7 +3308,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gethyperlinknavigateuri
 		// HRESULT GetHyperlinkNavigateUri( IUri **hyperlinkUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IUri GetHyperlinkNavigateUri();
+		new IUri? GetHyperlinkNavigateUri();
 
 		/// <summary>Sets the destination URI of the visual's hyperlink.</summary>
 		/// <param name="hyperlinkUri">The IUri interface that contains the destination URI of the visual's hyperlink.</param>
@@ -3316,7 +3319,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-sethyperlinknavigateuri
 		// HRESULT SetHyperlinkNavigateUri( IUri *hyperlinkUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetHyperlinkNavigateUri([In] IUri hyperlinkUri);
+		new void SetHyperlinkNavigateUri([In] IUri? hyperlinkUri);
 
 		/// <summary>Gets the <c>Language</c> property of the visual and of its contents.</summary>
 		/// <returns>
@@ -3330,7 +3333,7 @@ public static partial class XpsObjectModel
 		// GetLanguage( LPWSTR *language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetLanguage();
+		new string? GetLanguage();
 
 		/// <summary>Sets the <c>Language</c> property of the visual.</summary>
 		/// <param name="language">
@@ -3343,14 +3346,14 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setlanguage HRESULT
 		// SetLanguage( LPCWSTR language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string language);
+		new void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string? language);
 
 		/// <summary>Gets the text in unescaped UTF-16 scalar values.</summary>
 		/// <returns>The UTF-16 Unicode string of the text to be displayed. If the string is empty, a <c>NULL</c> pointer is returned.</returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-getunicodestring HRESULT
 		// GetUnicodeString( LPWSTR *unicodeString );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetUnicodeString();
+		string? GetUnicodeString();
 
 		/// <summary>Gets the number of Glyph indices.</summary>
 		/// <returns>The number of glyph indices.</returns>
@@ -3433,7 +3436,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-getprohibitedcaretstops
 		// HRESULT GetProhibitedCaretStops( UINT32 *prohibitedCaretStopCount, UINT32 *prohibitedCaretStops );
-		void GetProhibitedCaretStops(ref uint prohibitedCaretStopCount, [In, Out] uint[] prohibitedCaretStops);
+		void GetProhibitedCaretStops(ref uint prohibitedCaretStopCount, [In, Out] uint[]? prohibitedCaretStops);
 
 		/// <summary>Gets the level of bidirectional text.</summary>
 		/// <returns>
@@ -3490,7 +3493,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-getdevicefontname HRESULT
 		// GetDeviceFontName( LPWSTR *deviceFontName );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetDeviceFontName();
+		string? GetDeviceFontName();
 
 		/// <summary>Gets the style simulations that will be applied when rendering the glyphs.</summary>
 		/// <returns>The XPS_STYLE_SIMULATION value that describes the style simulations to be applied.</returns>
@@ -3652,7 +3655,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The fill brush is used to fill the shape of the rendered glyphs.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-getfillbrush HRESULT
 		// GetFillBrush( IXpsOMBrush **fillBrush );
-		IXpsOMBrush GetFillBrush();
+		IXpsOMBrush? GetFillBrush();
 
 		/// <summary>Gets a pointer to the local, unshared IXpsOMBrush interface of the fill brush to be used for the text.</summary>
 		/// <returns>
@@ -3681,7 +3684,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-getfillbrushlocal HRESULT
 		// GetFillBrushLocal( IXpsOMBrush **fillBrush );
-		IXpsOMBrush GetFillBrushLocal();
+		IXpsOMBrush? GetFillBrushLocal();
 
 		/// <summary>Sets the IXpsOMBrush interface pointer to a local, unshared fill brush.</summary>
 		/// <param name="fillBrush">
@@ -3725,7 +3728,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-setfillbrushlocal HRESULT
 		// SetFillBrushLocal( IXpsOMBrush *fillBrush );
-		void SetFillBrushLocal([In] IXpsOMBrush fillBrush);
+		void SetFillBrushLocal([In] IXpsOMBrush? fillBrush);
 
 		/// <summary>
 		/// Gets the lookup key of the IXpsOMBrush interface that is stored in a resource dictionary and will be used as the fill brush.
@@ -3757,7 +3760,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-getfillbrushlookup HRESULT
 		// GetFillBrushLookup( LPWSTR *key );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetFillBrushLookup();
+		string? GetFillBrushLookup();
 
 		/// <summary>Sets the lookup key name of a shared fill brush.</summary>
 		/// <param name="key">
@@ -3802,7 +3805,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphs-setfillbrushlookup HRESULT
 		// SetFillBrushLookup( LPCWSTR key );
-		void SetFillBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		void SetFillBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets a pointer to the IXpsOMGlyphsEditor interface that will be used to edit the glyphs in the object.</summary>
 		/// <returns>A pointer to the IXpsOMGlyphsEditor interface.</returns>
@@ -3837,13 +3840,13 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-getunicodestring
 		// HRESULT GetUnicodeString( LPWSTR *unicodeString );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetUnicodeString();
+		string? GetUnicodeString();
 
 		/// <summary>Sets the text in unescaped UTF-16 scalar values.</summary>
 		/// <param name="unicodeString">The address of a UTF-16 Unicode string. A <c>NULL</c> pointer clears the property.</param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-setunicodestring
 		// HRESULT SetUnicodeString( LPCWSTR unicodeString );
-		void SetUnicodeString([In, MarshalAs(UnmanagedType.LPWStr)] string unicodeString);
+		void SetUnicodeString([In, MarshalAs(UnmanagedType.LPWStr)] string? unicodeString);
 
 		/// <summary>Gets the number of glyph indices.</summary>
 		/// <returns>The glyph index count.</returns>
@@ -3882,7 +3885,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-setglyphindices
 		// HRESULT SetGlyphIndices( UINT32 indexCount, const XPS_GLYPH_INDEX *glyphIndices );
-		void SetGlyphIndices([In] uint indexCount, [In] XPS_GLYPH_INDEX[] glyphIndices);
+		void SetGlyphIndices([In] uint indexCount, [In] XPS_GLYPH_INDEX[]? glyphIndices);
 
 		/// <summary>Gets the number of glyph mappings.</summary>
 		/// <returns>The number of glyph mappings.</returns>
@@ -3918,7 +3921,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-setglyphmappings
 		// HRESULT SetGlyphMappings( UINT32 glyphMappingCount, const XPS_GLYPH_MAPPING *glyphMappings );
-		void SetGlyphMappings([In] uint glyphMappingCount, [In] XPS_GLYPH_MAPPING[] glyphMappings);
+		void SetGlyphMappings([In] uint glyphMappingCount, [In] XPS_GLYPH_MAPPING[]? glyphMappings);
 
 		/// <summary>Gets the number of prohibited caret stops.</summary>
 		/// <returns>The number of prohibited caret stops.</returns>
@@ -3955,7 +3958,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-getprohibitedcaretstops
 		// HRESULT GetProhibitedCaretStops( UINT32 *count, UINT32 *prohibitedCaretStops );
-		void GetProhibitedCaretStops(ref uint count, [In, Out] uint[] prohibitedCaretStops);
+		void GetProhibitedCaretStops(ref uint count, [In, Out] uint[]? prohibitedCaretStops);
 
 		/// <summary>Sets an array of prohibited caret stop locations.</summary>
 		/// <param name="count">
@@ -3973,7 +3976,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-setprohibitedcaretstops
 		// HRESULT SetProhibitedCaretStops( UINT32 count, const UINT32 *prohibitedCaretStops );
-		void SetProhibitedCaretStops([In] uint count, [In] uint[] prohibitedCaretStops);
+		void SetProhibitedCaretStops([In] uint count, [In] uint[]? prohibitedCaretStops);
 
 		/// <summary>Gets the bidirectional text level of the parent IXpsOMGlyphs interface.</summary>
 		/// <returns>
@@ -4066,7 +4069,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-getdevicefontname
 		// HRESULT GetDeviceFontName( LPWSTR *deviceFontName );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetDeviceFontName();
+		string? GetDeviceFontName();
 
 		/// <summary>Sets the name of the device font.</summary>
 		/// <param name="deviceFontName">
@@ -4078,7 +4081,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomglyphseditor-setdevicefontname
 		// HRESULT SetDeviceFontName( LPCWSTR deviceFontName );
-		void SetDeviceFontName([In, MarshalAs(UnmanagedType.LPWStr)] string deviceFontName);
+		void SetDeviceFontName([In, MarshalAs(UnmanagedType.LPWStr)] string? deviceFontName);
 	}
 
 	/// <summary>
@@ -4215,7 +4218,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **transform );
-		IXpsOMMatrixTransform GetTransform();
+		IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared, resolved matrix transform for the brush.
@@ -4251,7 +4254,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransformlocal
 		// HRESULT GetTransformLocal( IXpsOMMatrixTransform **transform );
-		IXpsOMMatrixTransform GetTransformLocal();
+		IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>
 		/// Sets the IXpsOMMatrixTransform interface pointer to a local, unshared matrix transform that is to be used for the brush.
@@ -4301,7 +4304,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-settransformlocal
 		// HRESULT SetTransformLocal( IXpsOMMatrixTransform *transform );
-		void SetTransformLocal([In] IXpsOMMatrixTransform transform);
+		void SetTransformLocal([In] IXpsOMMatrixTransform? transform);
 
 		/// <summary>
 		/// <para>Gets the name of the lookup key of the shared matrix transform interface that is to be used for the brush.</para>
@@ -4347,7 +4350,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransformlookup
 		// HRESULT GetTransformLookup( LPWSTR *key );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetTransformLookup();
+		string? GetTransformLookup();
 
 		/// <summary>
 		/// <para>Sets the name of the lookup key of a shared matrix transform that is to be used for the brush.</para>
@@ -4395,7 +4398,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-settransformlookup
 		// HRESULT SetTransformLookup( LPCWSTR key );
-		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the XPS_SPREAD_METHOD value, which describes how the area outside of the gradient region will be rendered.</summary>
 		/// <returns>
@@ -4481,7 +4484,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientstop-getowner HRESULT
 		// GetOwner( IXpsOMGradientBrush **owner );
-		IXpsOMGradientBrush GetOwner();
+		IXpsOMGradientBrush? GetOwner();
 
 		/// <summary>Gets the offset value of the gradient stop.</summary>
 		/// <returns>The offset value of the gradient stop, expressed as a fraction of the gradient path.</returns>
@@ -4511,7 +4514,7 @@ public static partial class XpsObjectModel
 		/// <remarks>A color profile is only returned when the color type of color is XPS_COLOR_TYPE_CONTEXT.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientstop-getcolor HRESULT
 		// GetColor( XPS_COLOR *color, IXpsOMColorProfileResource **colorProfile );
-		IXpsOMColorProfileResource GetColor(out XPS_COLOR color);
+		IXpsOMColorProfileResource? GetColor(out XPS_COLOR color);
 
 		/// <summary>Sets the color value and color profile of the gradient stop.</summary>
 		/// <param name="color">
@@ -4532,7 +4535,7 @@ public static partial class XpsObjectModel
 		/// <remarks>A color profile is only required when the color type of color is XPS_COLOR_TYPE_CONTEXT.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientstop-setcolor HRESULT
 		// SetColor( const XPS_COLOR *color, IXpsOMColorProfileResource *colorProfile );
-		void SetColor(in XPS_COLOR color, [In] IXpsOMColorProfileResource colorProfile);
+		void SetColor(in XPS_COLOR color, [In] IXpsOMColorProfileResource? colorProfile);
 
 		/// <summary>Makes a deep copy of the IXpsOMGradientStop interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>
@@ -4706,7 +4709,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransform();
+		new IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared resolved matrix transform for the brush.
@@ -4741,7 +4744,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransformLocal();
+		new IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the IXpsOMMatrixTransform interface pointer to a local, unshared matrix transform.</summary>
 		/// <param name="transform">
@@ -4789,7 +4792,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *transform );
-		new void SetTransformLocal([In] IXpsOMMatrixTransform transform);
+		new void SetTransformLocal([In] IXpsOMMatrixTransform? transform);
 
 		/// <summary>
 		/// Gets the lookup key that identifies the IXpsOMMatrixTransform interface in a resource dictionary that contains the resolved
@@ -4829,7 +4832,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransformlookup
 		// HRESULT GetTransformLookup( LPWSTR *key );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetTransformLookup();
+		new string? GetTransformLookup();
 
 		/// <summary>
 		/// Sets the lookup key name of a shared matrix transform that will be used as the transform for this brush.The shared matrix
@@ -4881,7 +4884,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-settransformlookup
 		// HRESULT SetTransformLookup( LPCWSTR key );
-		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the portion of the source image to be used by the tile.</summary>
 		/// <returns>The XPS_RECT structure that describes the area of the source content to be used by the tile.</returns>
@@ -4988,7 +4991,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomimagebrush-getimageresource HRESULT
 		// GetImageResource( IXpsOMImageResource **imageResource );
-		IXpsOMImageResource GetImageResource();
+		IXpsOMImageResource? GetImageResource();
 
 		/// <summary>
 		/// Sets a pointer to the IXpsOMImageResource interface that contains the image resource to be used as the source for the brush.
@@ -4999,7 +5002,7 @@ public static partial class XpsObjectModel
 		/// <remarks>The image resource must be of type JPEG, PNG, TIFF 6.0, or HD Photo.</remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomimagebrush-setimageresource HRESULT
 		// SetImageResource( IXpsOMImageResource *imageResource );
-		void SetImageResource([In] IXpsOMImageResource imageResource);
+		void SetImageResource([In] IXpsOMImageResource? imageResource);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMColorProfileResource interface, which contains the color profile resource that is associated
@@ -5015,7 +5018,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomimagebrush-getcolorprofileresource
 		// HRESULT GetColorProfileResource( IXpsOMColorProfileResource **colorProfileResource );
-		IXpsOMColorProfileResource GetColorProfileResource();
+		IXpsOMColorProfileResource? GetColorProfileResource();
 
 		/// <summary>
 		/// Sets a pointer to the IXpsOMColorProfileResource interface, which contains the color profile resource that is associated
@@ -5027,7 +5030,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomimagebrush-setcolorprofileresource
 		// HRESULT SetColorProfileResource( IXpsOMColorProfileResource *colorProfileResource );
-		void SetColorProfileResource([In] IXpsOMColorProfileResource colorProfileResource);
+		void SetColorProfileResource([In] IXpsOMColorProfileResource? colorProfileResource);
 
 		/// <summary>Makes a deep copy of the interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>
@@ -5052,7 +5055,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -5065,7 +5068,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a new, read-only copy of the stream that is associated with this resource.</summary>
 		/// <returns>A new, read-only copy of the stream that is associated with this resource.</returns>
@@ -5160,4 +5163,38 @@ public static partial class XpsObjectModel
 		/// <summary>A non-negative value that represents the object's size in the vertical (y) dimension.</summary>
 		public float height;
 	}
+
+	/// <summary>Wrapper for all IXpsXXXCollection interfaces. This class is used to wrap the collection interfaces.</summary>
+	/// <typeparam name="T">The element type.</typeparam>
+	public class XpsList<T> : VirtualList<T>
+	{
+		/// <summary>Initializes a new instance of the <see cref="XpsList{T}"/> class.</summary>
+		/// <param name="collection">The collection.</param>
+		public XpsList(object collection) : base(new Impl(collection))
+		{
+		}
+
+		private class Impl : IVirtualListMethods<T>
+		{
+			private readonly object collection;
+
+			public Impl(object collection) => this.collection = collection;
+
+			bool IVirtualReadOnlyListMethods<T>.TryGet(int index, [NotNullWhen(true)] out T? value)
+			{
+				value = collection.InvokeMethod<T>("GetAt", (uint)index);
+				return value is not null;
+			}
+
+			void IVirtualListMethods<T>.SetItemAt(int index, T value) => collection.InvokeMethod("SetAt", (uint)index, value);
+
+			int IVirtualReadOnlyListMethods<T>.GetItemCount() => (int)collection.InvokeMethod<uint>("GetCount");
+
+			void IVirtualListMethods<T>.AddItem(T item) => collection.InvokeMethod("Append", item);
+
+			void IVirtualListMethods<T>.InsertItemAt(int index, T item) => collection.InvokeMethod("InsertAt", (uint)index, item);
+
+			void IVirtualListMethods<T>.RemoveItemAt(int index) => collection.InvokeMethod("RemoveAt", (uint)index);
+		}
+	}
 }

PInvoke/Printing/XpsObjectModel2.cs

@@ -98,7 +98,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomimageresourcecollection-getbypartname
 		// HRESULT GetByPartName( IOpcPartUri *partName, IXpsOMImageResource **part );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMImageResource GetByPartName([In] IOpcPartUri partName);
+		IXpsOMImageResource? GetByPartName([In] IOpcPartUri partName);
 	}
 
 	/// <summary>Specifies a linear gradient, which is the color gradient along a vector.</summary>
@@ -214,7 +214,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransform();
+		new IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared, resolved matrix transform for the brush.
@@ -250,7 +250,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransformlocal
 		// HRESULT GetTransformLocal( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransformLocal();
+		new IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>
 		/// Sets the IXpsOMMatrixTransform interface pointer to a local, unshared matrix transform that is to be used for the brush.
@@ -300,7 +300,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-settransformlocal
 		// HRESULT SetTransformLocal( IXpsOMMatrixTransform *transform );
-		new void SetTransformLocal([In] IXpsOMMatrixTransform transform);
+		new void SetTransformLocal([In] IXpsOMMatrixTransform? transform);
 
 		/// <summary>
 		/// <para>Gets the name of the lookup key of the shared matrix transform interface that is to be used for the brush.</para>
@@ -346,7 +346,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransformlookup
 		// HRESULT GetTransformLookup( LPWSTR *key );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetTransformLookup();
+		new string? GetTransformLookup();
 
 		/// <summary>
 		/// <para>Sets the name of the lookup key of a shared matrix transform that is to be used for the brush.</para>
@@ -394,7 +394,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-settransformlookup
 		// HRESULT SetTransformLookup( LPCWSTR key );
-		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the XPS_SPREAD_METHOD value, which describes how the area outside of the gradient region will be rendered.</summary>
 		/// <returns>
@@ -531,7 +531,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomnamecollection-getat HRESULT GetAt(
 		// UINT32 index, LPWSTR *name );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetAt([In] uint index);
+		string? GetAt([In] uint index);
 	}
 
 	/// <summary>Describes a non-text visual item.</summary>
@@ -586,7 +586,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMMatrixTransform GetTransform();
+		new IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared, resolved matrix transform for the visual.
@@ -619,7 +619,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMMatrixTransform GetTransformLocal();
+		new IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the local, unshared matrix transform.</summary>
 		/// <param name="matrixTransform">
@@ -664,7 +664,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetTransformLocal([In] IXpsOMMatrixTransform matrixTransform);
+		new void SetTransformLocal([In] IXpsOMMatrixTransform? matrixTransform);
 
 		/// <summary>
 		/// Gets the lookup key name of the IXpsOMMatrixTransform interface in a resource dictionary that contains the resolved matrix
@@ -699,7 +699,7 @@ public static partial class XpsObjectModel
 		// GetTransformLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetTransformLookup();
+		new string? GetTransformLookup();
 
 		/// <summary>Sets the lookup key name of a shared matrix transform in a resource dictionary.</summary>
 		/// <param name="key">The lookup key name of the matrix transform in the dictionary.</param>
@@ -742,7 +742,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlookup HRESULT
 		// SetTransformLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the resolved geometry of the visual's clipping region.
@@ -778,7 +778,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometry HRESULT
 		// GetClipGeometry( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMGeometry GetClipGeometry();
+		new IXpsOMGeometry? GetClipGeometry();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the local, unshared geometry of the visual's clipping region.
@@ -810,7 +810,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometrylocal HRESULT
 		// GetClipGeometryLocal( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMGeometry GetClipGeometryLocal();
+		new IXpsOMGeometry? GetClipGeometryLocal();
 
 		/// <summary>Sets the local, unshared clipping region for the visual.</summary>
 		/// <param name="clipGeometry">
@@ -856,7 +856,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylocal HRESULT
 		// SetClipGeometryLocal( IXpsOMGeometry *clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetClipGeometryLocal([In] IXpsOMGeometry clipGeometry);
+		new void SetClipGeometryLocal([In] IXpsOMGeometry? clipGeometry);
 
 		/// <summary>
 		/// Gets the lookup key for the IXpsOMGeometry interface in a resource dictionary that contains the visual's clipping region.
@@ -889,7 +889,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetClipGeometryLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetClipGeometryLookup();
+		new string? GetClipGeometryLookup();
 
 		/// <summary>Sets the lookup key name of a shared clip geometry in a resource dictionary.</summary>
 		/// <param name="key">
@@ -934,7 +934,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylookup
 		// HRESULT SetClipGeometryLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the opacity value of this visual.</summary>
 		/// <returns>The opacity value.</returns>
@@ -988,7 +988,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrush HRESULT
 		// GetOpacityMaskBrush( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMBrush GetOpacityMaskBrush();
+		new IXpsOMBrush? GetOpacityMaskBrush();
 
 		/// <summary>Gets the local, unshared opacity mask brush for the visual.</summary>
 		/// <returns>
@@ -1018,7 +1018,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrushlocal
 		// HRESULT GetOpacityMaskBrushLocal( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IXpsOMBrush GetOpacityMaskBrushLocal();
+		new IXpsOMBrush? GetOpacityMaskBrushLocal();
 
 		/// <summary>Sets the IXpsOMBrush interface pointer as the local, unshared opacity mask brush.</summary>
 		/// <param name="opacityMaskBrush">
@@ -1064,7 +1064,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlocal
 		// HRESULT SetOpacityMaskBrushLocal( IXpsOMBrush *opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetOpacityMaskBrushLocal([In] IXpsOMBrush opacityMaskBrush);
+		new void SetOpacityMaskBrushLocal([In] IXpsOMBrush? opacityMaskBrush);
 
 		/// <summary>Gets the name of the lookup key of the shared opacity mask brush in a resource dictionary.</summary>
 		/// <returns>
@@ -1095,7 +1095,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetOpacityMaskBrushLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetOpacityMaskBrushLookup();
+		new string? GetOpacityMaskBrushLookup();
 
 		/// <summary>Sets the lookup key name of a shared opacity mask brush in a resource dictionary.</summary>
 		/// <param name="key">
@@ -1140,7 +1140,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlookup
 		// HRESULT SetOpacityMaskBrushLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the <c>Name</c> property of the visual.</summary>
 		/// <returns>The <c>Name</c> property string. If the <c>Name</c> property has not been set, a <c>NULL</c> pointer is returned.</returns>
@@ -1148,7 +1148,7 @@ public static partial class XpsObjectModel
 		// LPWSTR *name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetName();
+		new string? GetName();
 
 		/// <summary>Sets the <c>Name</c> property of the visual.</summary>
 		/// <param name="name">The name of the visual. A <c>NULL</c> pointer clears the <c>Name</c> property.</param>
@@ -1161,7 +1161,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setname HRESULT SetName(
 		// LPCWSTR name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string name);
+		new void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string? name);
 
 		/// <summary>Gets a value that indicates whether the visual is the target of a hyperlink.</summary>
 		/// <returns>
@@ -1219,7 +1219,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gethyperlinknavigateuri
 		// HRESULT GetHyperlinkNavigateUri( IUri **hyperlinkUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IUri GetHyperlinkNavigateUri();
+		new IUri? GetHyperlinkNavigateUri();
 
 		/// <summary>Sets the destination URI of the visual's hyperlink.</summary>
 		/// <param name="hyperlinkUri">The IUri interface that contains the destination URI of the visual's hyperlink.</param>
@@ -1244,7 +1244,7 @@ public static partial class XpsObjectModel
 		// GetLanguage( LPWSTR *language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetLanguage();
+		new string? GetLanguage();
 
 		/// <summary>Sets the <c>Language</c> property of the visual.</summary>
 		/// <param name="language">
@@ -1257,7 +1257,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setlanguage HRESULT
 		// SetLanguage( LPCWSTR language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string language);
+		new void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string? language);
 
 		/// <summary>Gets a pointer to the path's IXpsOMGeometry interface, which describes the resolved fill area for this path.</summary>
 		/// <returns>
@@ -1289,7 +1289,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getgeometry HRESULT
 		// GetGeometry( IXpsOMGeometry **geometry );
-		IXpsOMGeometry GetGeometry();
+		IXpsOMGeometry? GetGeometry();
 
 		/// <summary>Gets the local, unshared geometry of the resolved fill area for this path.</summary>
 		/// <returns>
@@ -1318,7 +1318,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getgeometrylocal HRESULT
 		// GetGeometryLocal( IXpsOMGeometry **geometry );
-		IXpsOMGeometry GetGeometryLocal();
+		IXpsOMGeometry? GetGeometryLocal();
 
 		/// <summary>
 		/// Sets the pointer to the local, unshared IXpsOMGeometry interface that contains the geometry of the resolved fill area to be
@@ -1365,7 +1365,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-setgeometrylocal HRESULT
 		// SetGeometryLocal( IXpsOMGeometry *geometry );
-		void SetGeometryLocal([In] IXpsOMGeometry geometry);
+		void SetGeometryLocal([In] IXpsOMGeometry? geometry);
 
 		/// <summary>
 		/// Gets the lookup key of a shared geometry object that is stored in a resource dictionary and that describes the resolved fill
@@ -1398,7 +1398,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getgeometrylookup HRESULT
 		// GetGeometryLookup( LPWSTR *lookup );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetGeometryLookup();
+		string? GetGeometryLookup();
 
 		/// <summary>
 		/// <para>Sets the lookup key name of a shared geometry in a resource dictionary.</para>
@@ -1441,7 +1441,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-setgeometrylookup HRESULT
 		// SetGeometryLookup( LPCWSTR lookup );
-		void SetGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string lookup);
+		void SetGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? lookup);
 
 		/// <summary>
 		/// Gets the short textual description of the object's contents. This description is used by accessibility clients to describe
@@ -1459,7 +1459,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getaccessibilityshortdescription
 		// HRESULT GetAccessibilityShortDescription( LPWSTR *shortDescription );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetAccessibilityShortDescription();
+		string? GetAccessibilityShortDescription();
 
 		/// <summary>
 		/// Sets the short textual description of the object's contents. This description is used by accessibility clients to describe
@@ -1490,7 +1490,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getaccessibilitylongdescription
 		// HRESULT GetAccessibilityLongDescription( LPWSTR *longDescription );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetAccessibilityLongDescription();
+		string? GetAccessibilityLongDescription();
 
 		/// <summary>
 		/// Sets the long (detailed) textual description of the object's contents. This description is used by accessibility clients to
@@ -1590,7 +1590,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getstrokebrush HRESULT
 		// GetStrokeBrush( IXpsOMBrush **brush );
-		IXpsOMBrush GetStrokeBrush();
+		IXpsOMBrush? GetStrokeBrush();
 
 		/// <summary>Gets a pointer to the local, unshared IXpsOMBrush interface that contains the stroke brush for the path.</summary>
 		/// <returns>
@@ -1619,7 +1619,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getstrokebrushlocal HRESULT
 		// GetStrokeBrushLocal( IXpsOMBrush **brush );
-		IXpsOMBrush GetStrokeBrushLocal();
+		IXpsOMBrush? GetStrokeBrushLocal();
 
 		/// <summary>Sets a pointer to a local, unshared IXpsOMBrush interface to be used as a stroke brush.</summary>
 		/// <param name="brush">A pointer to a local, unshared IXpsOMBrush interface to be used as a stroke brush.</param>
@@ -1660,7 +1660,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-setstrokebrushlocal HRESULT
 		// SetStrokeBrushLocal( IXpsOMBrush *brush );
-		void SetStrokeBrushLocal([In] IXpsOMBrush brush);
+		void SetStrokeBrushLocal([In] IXpsOMBrush? brush);
 
 		/// <summary>
 		/// Gets the lookup key of the brush that is stored in a resource dictionary and is to be used as the stroke brush for the path.
@@ -1692,7 +1692,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getstrokebrushlookup HRESULT
 		// GetStrokeBrushLookup( LPWSTR *lookup );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetStrokeBrushLookup();
+		string? GetStrokeBrushLookup();
 
 		/// <summary>
 		/// Sets the lookup key name of a shared brush to be used as the stroke brush.The shared brush is stored in a resource dictionary.
@@ -1734,7 +1734,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-setstrokebrushlookup HRESULT
 		// SetStrokeBrushLookup( LPCWSTR lookup );
-		void SetStrokeBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string lookup);
+		void SetStrokeBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? lookup);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMDashCollection interface that contains the XPS_DASH structures that define the dash pattern of
@@ -1905,7 +1905,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getfillbrush HRESULT
 		// GetFillBrush( IXpsOMBrush **brush );
-		IXpsOMBrush GetFillBrush();
+		IXpsOMBrush? GetFillBrush();
 
 		/// <summary>Gets a pointer to the local, unshared IXpsOMBrush interface that contains the fill brush for the path.</summary>
 		/// <returns>
@@ -1935,7 +1935,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getfillbrushlocal HRESULT
 		// GetFillBrushLocal( IXpsOMBrush **brush );
-		IXpsOMBrush GetFillBrushLocal();
+		IXpsOMBrush? GetFillBrushLocal();
 
 		/// <summary>Sets the pointer to the local, unshared IXpsOMBrush interface to be used as the fill brush.</summary>
 		/// <param name="brush">A pointer to the local, unshared IXpsOMBrush interface to be used as the fill brush.</param>
@@ -1976,7 +1976,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-setfillbrushlocal HRESULT
 		// SetFillBrushLocal( IXpsOMBrush *brush );
-		void SetFillBrushLocal([In] IXpsOMBrush brush);
+		void SetFillBrushLocal([In] IXpsOMBrush? brush);
 
 		/// <summary>
 		/// Gets the lookup key of the brush that is stored in a resource dictionary and used as the fill brush for the path.
@@ -2008,7 +2008,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-getfillbrushlookup HRESULT
 		// GetFillBrushLookup( LPWSTR *lookup );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetFillBrushLookup();
+		string? GetFillBrushLookup();
 
 		/// <summary>Sets the lookup key name of a shared brush in a resource dictionary, to be used as the fill brush.</summary>
 		/// <param name="lookup">The key name of the brush in a resource dictionary, to be used as the fill brush.</param>
@@ -2048,7 +2048,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompath-setfillbrushlookup HRESULT
 		// SetFillBrushLookup( LPCWSTR lookup );
-		void SetFillBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string lookup);
+		void SetFillBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? lookup);
 
 		/// <summary>Makes a deep copy of the interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>
@@ -2071,7 +2071,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -2084,7 +2084,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a new, read-only copy of the stream that is associated with this resource.</summary>
 		/// <returns>A new, read-only copy of the stream that is associated with this resource.</returns>
@@ -2228,7 +2228,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransform();
+		new IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared, resolved matrix transform for the brush.
@@ -2264,7 +2264,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransformlocal
 		// HRESULT GetTransformLocal( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransformLocal();
+		new IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>
 		/// Sets the IXpsOMMatrixTransform interface pointer to a local, unshared matrix transform that is to be used for the brush.
@@ -2314,7 +2314,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-settransformlocal
 		// HRESULT SetTransformLocal( IXpsOMMatrixTransform *transform );
-		new void SetTransformLocal([In] IXpsOMMatrixTransform transform);
+		new void SetTransformLocal([In] IXpsOMMatrixTransform? transform);
 
 		/// <summary>
 		/// <para>Gets the name of the lookup key of the shared matrix transform interface that is to be used for the brush.</para>
@@ -2360,7 +2360,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-gettransformlookup
 		// HRESULT GetTransformLookup( LPWSTR *key );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetTransformLookup();
+		new string? GetTransformLookup();
 
 		/// <summary>
 		/// <para>Sets the name of the lookup key of a shared matrix transform that is to be used for the brush.</para>
@@ -2408,7 +2408,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomgradientbrush-settransformlookup
 		// HRESULT SetTransformLookup( LPCWSTR key );
-		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the XPS_SPREAD_METHOD value, which describes how the area outside of the gradient region will be rendered.</summary>
 		/// <returns>
@@ -2587,7 +2587,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -2600,7 +2600,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a pointer to the IXpsOMDictionary interface of the remote dictionary that is associated with this resource.</summary>
 		/// <returns>A pointer to the IXpsOMDictionary interface of the dictionary that is associated with this resource.</returns>
@@ -2711,7 +2711,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomremotedictionaryresourcecollection-getbypartname
 		// HRESULT GetByPartName( IOpcPartUri *partName, IXpsOMRemoteDictionaryResource **remoteDictionaryResource );
-		IXpsOMRemoteDictionaryResource GetByPartName([In] IOpcPartUri partName);
+		IXpsOMRemoteDictionaryResource? GetByPartName([In] IOpcPartUri partName);
 	}
 
 	/// <summary>Used as the base interface for the resource interfaces of the XPS object model.</summary>
@@ -2728,7 +2728,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -2741,7 +2741,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 	}
 
 	/// <summary>The base interface for sharable interfaces.</summary>
@@ -2778,7 +2778,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -2791,7 +2791,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a pointer to the IXpsOMDocument interface that contains the resource.</summary>
 		/// <returns>
@@ -2801,7 +2801,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomsignatureblockresource-getowner
 		// HRESULT GetOwner( IXpsOMDocument **owner );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMDocument GetOwner();
+		IXpsOMDocument? GetOwner();
 
 		/// <summary>Gets a new, read-only copy of the stream that is associated with this resource.</summary>
 		/// <returns>A new, read-only copy of the stream that is associated with this resource.</returns>
@@ -2931,7 +2931,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomsignatureblockresourcecollection-getbypartname
 		// HRESULT GetByPartName( IOpcPartUri *partName, IXpsOMSignatureBlockResource **signatureBlockResource );
-		IXpsOMSignatureBlockResource GetByPartName([In] IOpcPartUri partName);
+		IXpsOMSignatureBlockResource? GetByPartName([In] IOpcPartUri partName);
 	}
 
 	/// <summary>A single-color brush.</summary>
@@ -2985,7 +2985,7 @@ public static partial class XpsObjectModel
 		/// </returns>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomsolidcolorbrush-getcolor HRESULT
 		// GetColor( XPS_COLOR *color, IXpsOMColorProfileResource **colorProfile );
-		IXpsOMColorProfileResource GetColor(out XPS_COLOR color);
+		IXpsOMColorProfileResource? GetColor(out XPS_COLOR color);
 
 		/// <summary>Sets the color value and color profile of the brush.</summary>
 		/// <param name="color">
@@ -3005,7 +3005,7 @@ public static partial class XpsObjectModel
 		/// </param>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomsolidcolorbrush-setcolor HRESULT
 		// SetColor( const XPS_COLOR *color, IXpsOMColorProfileResource *colorProfile );
-		void SetColor(in XPS_COLOR color, [In] IXpsOMColorProfileResource colorProfile);
+		void SetColor(in XPS_COLOR color, [In] IXpsOMColorProfileResource? colorProfile);
 
 		/// <summary>Makes a deep copy of the interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>
@@ -3037,7 +3037,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-getpartname HRESULT
 		// GetPartName( IOpcPartUri **partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new IOpcPartUri GetPartName();
+		new IOpcPartUri? GetPartName();
 
 		/// <summary>Sets the name that will be used when the part is serialized.</summary>
 		/// <param name="partUri">
@@ -3050,7 +3050,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsompart-setpartname HRESULT
 		// SetPartName( IOpcPartUri *partUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		new void SetPartName([In] IOpcPartUri partUri);
+		new void SetPartName([In] IOpcPartUri? partUri);
 
 		/// <summary>Gets a pointer to the IXpsOMPage interface that contains this resource.</summary>
 		/// <returns>
@@ -3060,7 +3060,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomstoryfragmentsresource-getowner
 		// HRESULT GetOwner( IXpsOMPageReference **owner );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMPageReference GetOwner();
+		IXpsOMPageReference? GetOwner();
 
 		/// <summary>Gets a new, read-only copy of the stream that is associated with this resource.</summary>
 		/// <returns>A new, read-only copy of the stream that is associated with this resource.</returns>
@@ -3231,7 +3231,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **transform );
-		IXpsOMMatrixTransform GetTransform();
+		IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared resolved matrix transform for the brush.
@@ -3266,7 +3266,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **transform );
-		IXpsOMMatrixTransform GetTransformLocal();
+		IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the IXpsOMMatrixTransform interface pointer to a local, unshared matrix transform.</summary>
 		/// <param name="transform">
@@ -3314,7 +3314,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *transform );
-		void SetTransformLocal([In] IXpsOMMatrixTransform transform);
+		void SetTransformLocal([In] IXpsOMMatrixTransform? transform);
 
 		/// <summary>
 		/// Gets the lookup key that identifies the IXpsOMMatrixTransform interface in a resource dictionary that contains the resolved
@@ -3354,7 +3354,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransformlookup
 		// HRESULT GetTransformLookup( LPWSTR *key );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetTransformLookup();
+		string? GetTransformLookup();
 
 		/// <summary>
 		/// Sets the lookup key name of a shared matrix transform that will be used as the transform for this brush.The shared matrix
@@ -3406,7 +3406,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-settransformlookup
 		// HRESULT SetTransformLookup( LPCWSTR key );
-		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the portion of the source image to be used by the tile.</summary>
 		/// <returns>The XPS_RECT structure that describes the area of the source content to be used by the tile.</returns>
@@ -3553,7 +3553,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMMatrixTransform GetTransform();
+		IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared, resolved matrix transform for the visual.
@@ -3586,7 +3586,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMMatrixTransform GetTransformLocal();
+		IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the local, unshared matrix transform.</summary>
 		/// <param name="matrixTransform">
@@ -3631,7 +3631,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *matrixTransform );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetTransformLocal([In] IXpsOMMatrixTransform matrixTransform);
+		void SetTransformLocal([In] IXpsOMMatrixTransform? matrixTransform);
 
 		/// <summary>
 		/// Gets the lookup key name of the IXpsOMMatrixTransform interface in a resource dictionary that contains the resolved matrix
@@ -3666,7 +3666,7 @@ public static partial class XpsObjectModel
 		// GetTransformLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetTransformLookup();
+		string? GetTransformLookup();
 
 		/// <summary>Sets the lookup key name of a shared matrix transform in a resource dictionary.</summary>
 		/// <param name="key">The lookup key name of the matrix transform in the dictionary.</param>
@@ -3709,7 +3709,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-settransformlookup HRESULT
 		// SetTransformLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the resolved geometry of the visual's clipping region.
@@ -3745,7 +3745,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometry HRESULT
 		// GetClipGeometry( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMGeometry GetClipGeometry();
+		IXpsOMGeometry? GetClipGeometry();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMGeometry interface that contains the local, unshared geometry of the visual's clipping region.
@@ -3777,7 +3777,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getclipgeometrylocal HRESULT
 		// GetClipGeometryLocal( IXpsOMGeometry **clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMGeometry GetClipGeometryLocal();
+		IXpsOMGeometry? GetClipGeometryLocal();
 
 		/// <summary>Sets the local, unshared clipping region for the visual.</summary>
 		/// <param name="clipGeometry">
@@ -3823,7 +3823,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylocal HRESULT
 		// SetClipGeometryLocal( IXpsOMGeometry *clipGeometry );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetClipGeometryLocal([In] IXpsOMGeometry clipGeometry);
+		void SetClipGeometryLocal([In] IXpsOMGeometry? clipGeometry);
 
 		/// <summary>
 		/// Gets the lookup key for the IXpsOMGeometry interface in a resource dictionary that contains the visual's clipping region.
@@ -3856,7 +3856,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetClipGeometryLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetClipGeometryLookup();
+		string? GetClipGeometryLookup();
 
 		/// <summary>Sets the lookup key name of a shared clip geometry in a resource dictionary.</summary>
 		/// <param name="key">
@@ -3901,7 +3901,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setclipgeometrylookup
 		// HRESULT SetClipGeometryLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		void SetClipGeometryLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the opacity value of this visual.</summary>
 		/// <returns>The opacity value.</returns>
@@ -3955,7 +3955,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrush HRESULT
 		// GetOpacityMaskBrush( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMBrush GetOpacityMaskBrush();
+		IXpsOMBrush? GetOpacityMaskBrush();
 
 		/// <summary>Gets the local, unshared opacity mask brush for the visual.</summary>
 		/// <returns>
@@ -3985,7 +3985,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-getopacitymaskbrushlocal
 		// HRESULT GetOpacityMaskBrushLocal( IXpsOMBrush **opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IXpsOMBrush GetOpacityMaskBrushLocal();
+		IXpsOMBrush? GetOpacityMaskBrushLocal();
 
 		/// <summary>Sets the IXpsOMBrush interface pointer as the local, unshared opacity mask brush.</summary>
 		/// <param name="opacityMaskBrush">
@@ -4031,7 +4031,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlocal
 		// HRESULT SetOpacityMaskBrushLocal( IXpsOMBrush *opacityMaskBrush );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetOpacityMaskBrushLocal([In] IXpsOMBrush opacityMaskBrush);
+		void SetOpacityMaskBrushLocal([In] IXpsOMBrush? opacityMaskBrush);
 
 		/// <summary>Gets the name of the lookup key of the shared opacity mask brush in a resource dictionary.</summary>
 		/// <returns>
@@ -4062,7 +4062,7 @@ public static partial class XpsObjectModel
 		// HRESULT GetOpacityMaskBrushLookup( LPWSTR *key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetOpacityMaskBrushLookup();
+		string? GetOpacityMaskBrushLookup();
 
 		/// <summary>Sets the lookup key name of a shared opacity mask brush in a resource dictionary.</summary>
 		/// <param name="key">
@@ -4107,7 +4107,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setopacitymaskbrushlookup
 		// HRESULT SetOpacityMaskBrushLookup( LPCWSTR key );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		void SetOpacityMaskBrushLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the <c>Name</c> property of the visual.</summary>
 		/// <returns>The <c>Name</c> property string. If the <c>Name</c> property has not been set, a <c>NULL</c> pointer is returned.</returns>
@@ -4115,7 +4115,7 @@ public static partial class XpsObjectModel
 		// LPWSTR *name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetName();
+		string? GetName();
 
 		/// <summary>Sets the <c>Name</c> property of the visual.</summary>
 		/// <param name="name">The name of the visual. A <c>NULL</c> pointer clears the <c>Name</c> property.</param>
@@ -4128,7 +4128,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setname HRESULT SetName(
 		// LPCWSTR name );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string name);
+		void SetName([In, MarshalAs(UnmanagedType.LPWStr)] string? name);
 
 		/// <summary>Gets a value that indicates whether the visual is the target of a hyperlink.</summary>
 		/// <returns>
@@ -4186,7 +4186,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-gethyperlinknavigateuri
 		// HRESULT GetHyperlinkNavigateUri( IUri **hyperlinkUri );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		IUri GetHyperlinkNavigateUri();
+		IUri? GetHyperlinkNavigateUri();
 
 		/// <summary>Sets the destination URI of the visual's hyperlink.</summary>
 		/// <param name="hyperlinkUri">The IUri interface that contains the destination URI of the visual's hyperlink.</param>
@@ -4211,7 +4211,7 @@ public static partial class XpsObjectModel
 		// GetLanguage( LPWSTR *language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetLanguage();
+		string? GetLanguage();
 
 		/// <summary>Sets the <c>Language</c> property of the visual.</summary>
 		/// <param name="language">
@@ -4224,7 +4224,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisual-setlanguage HRESULT
 		// SetLanguage( LPCWSTR language );
 		[MethodImpl(MethodImplOptions.InternalCall)]
-		void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string language);
+		void SetLanguage([In, MarshalAs(UnmanagedType.LPWStr)] string? language);
 	}
 
 	/// <summary>A brush that uses a visual element as a source.</summary>
@@ -4305,7 +4305,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransform HRESULT
 		// GetTransform( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransform();
+		new IXpsOMMatrixTransform? GetTransform();
 
 		/// <summary>
 		/// Gets a pointer to the IXpsOMMatrixTransform interface that contains the local, unshared resolved matrix transform for the brush.
@@ -4340,7 +4340,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransformlocal HRESULT
 		// GetTransformLocal( IXpsOMMatrixTransform **transform );
-		new IXpsOMMatrixTransform GetTransformLocal();
+		new IXpsOMMatrixTransform? GetTransformLocal();
 
 		/// <summary>Sets the IXpsOMMatrixTransform interface pointer to a local, unshared matrix transform.</summary>
 		/// <param name="transform">
@@ -4388,7 +4388,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-settransformlocal HRESULT
 		// SetTransformLocal( IXpsOMMatrixTransform *transform );
-		new void SetTransformLocal([In] IXpsOMMatrixTransform transform);
+		new void SetTransformLocal([In] IXpsOMMatrixTransform? transform);
 
 		/// <summary>
 		/// Gets the lookup key that identifies the IXpsOMMatrixTransform interface in a resource dictionary that contains the resolved
@@ -4428,7 +4428,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-gettransformlookup
 		// HRESULT GetTransformLookup( LPWSTR *key );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		new string GetTransformLookup();
+		new string? GetTransformLookup();
 
 		/// <summary>
 		/// Sets the lookup key name of a shared matrix transform that will be used as the transform for this brush.The shared matrix
@@ -4480,7 +4480,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomtilebrush-settransformlookup
 		// HRESULT SetTransformLookup( LPCWSTR key );
-		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string key);
+		new void SetTransformLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? key);
 
 		/// <summary>Gets the portion of the source image to be used by the tile.</summary>
 		/// <returns>The XPS_RECT structure that describes the area of the source content to be used by the tile.</returns>
@@ -4611,7 +4611,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisualbrush-getvisual HRESULT
 		// GetVisual( IXpsOMVisual **visual );
-		IXpsOMVisual GetVisual();
+		IXpsOMVisual? GetVisual();
 
 		/// <summary>Gets a pointer to the interface of the local, unshared visual used as the source for the brush.</summary>
 		/// <returns>
@@ -4644,7 +4644,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisualbrush-getvisuallocal HRESULT
 		// GetVisualLocal( IXpsOMVisual **visual );
-		IXpsOMVisual GetVisualLocal();
+		IXpsOMVisual? GetVisualLocal();
 
 		/// <summary>Sets the interface pointer of the local, unshared visual used as the source for the brush.</summary>
 		/// <param name="visual">
@@ -4687,7 +4687,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisualbrush-setvisuallocal HRESULT
 		// SetVisualLocal( IXpsOMVisual *visual );
-		void SetVisualLocal([In] IXpsOMVisual visual);
+		void SetVisualLocal([In] IXpsOMVisual? visual);
 
 		/// <summary>
 		/// Gets the lookup key name of a visual in a resource dictionary; the visual is to be used as the source for the brush.
@@ -4719,7 +4719,7 @@ public static partial class XpsObjectModel
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisualbrush-getvisuallookup HRESULT
 		// GetVisualLookup( LPWSTR *lookup );
 		[return: MarshalAs(UnmanagedType.LPWStr)]
-		string GetVisualLookup();
+		string? GetVisualLookup();
 
 		/// <summary>
 		/// Sets the lookup key name of the shared visual, which is stored in a resource dictionary, to be used as the source for the brush.
@@ -4762,7 +4762,7 @@ public static partial class XpsObjectModel
 		/// </remarks>
 		// https://docs.microsoft.com/en-us/windows/win32/api/xpsobjectmodel/nf-xpsobjectmodel-ixpsomvisualbrush-setvisuallookup HRESULT
 		// SetVisualLookup( LPCWSTR lookup );
-		void SetVisualLookup([In, MarshalAs(UnmanagedType.LPWStr)] string lookup);
+		void SetVisualLookup([In, MarshalAs(UnmanagedType.LPWStr)] string? lookup);
 
 		/// <summary>Makes a deep copy of the interface.</summary>
 		/// <returns>A pointer to the copy of the interface.</returns>

PInvoke/Printing/XpsPrint.cs

@@ -313,7 +313,7 @@ public static partial class XpsPrint
 	[DllImport(Lib.XpsPrint, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("xpsprint.h", MSDNShortId = "d982ae2e-c68f-4197-b419-22a63e61db8a")]
 	public static extern HRESULT StartXpsPrintJob([MarshalAs(UnmanagedType.LPWStr)] string printerName, [Optional, MarshalAs(UnmanagedType.LPWStr)] string? jobName,
-		[Optional, MarshalAs(UnmanagedType.LPWStr)] string? outputFileName, [Optional] IntPtr progressEvent, [Optional] IntPtr completionEvent, [Optional] byte[]? printablePagesOn,
+		[Optional, MarshalAs(UnmanagedType.LPWStr)] string? outputFileName, [Optional] HEVENT progressEvent, [Optional] HEVENT completionEvent, [Optional] byte[]? printablePagesOn,
 		uint printablePagesOnCount, out IXpsPrintJob xpsPrintJob, out IXpsPrintJobStream documentStream, out IXpsPrintJobStream printTicketStream);
 
 	/// <summary>
@@ -439,7 +439,7 @@ public static partial class XpsPrint
 	[DllImport(Lib.XpsPrint, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("xpsprint.h", MSDNShortId = "91D0BA4D-60A6-43F8-8BD3-9183DC6CD50D")]
 	public static extern HRESULT StartXpsPrintJob1([MarshalAs(UnmanagedType.LPWStr)] string printerName, [Optional, MarshalAs(UnmanagedType.LPWStr)] string? jobName,
-		[Optional, MarshalAs(UnmanagedType.LPWStr)] string? outputFileName, [Optional] IntPtr progressEvent, [Optional] IntPtr completionEvent,
+		[Optional, MarshalAs(UnmanagedType.LPWStr)] string? outputFileName, [Optional] HEVENT progressEvent, [Optional] HEVENT completionEvent,
 		out IXpsPrintJob xpsPrintJob, out IntPtr printContentReceiver);
 
 	/// <summary>

PInvoke/Shared/WinBase/SYSTEMTIME.cs

@@ -317,8 +317,7 @@ public struct SYSTEMTIME : IEquatable<SYSTEMTIME>, IComparable<SYSTEMTIME>
 	{
 		var ticks1 = t1.ToUInt64;
 		var ticks2 = t2.ToUInt64;
-		if (ticks1 > ticks2) return 1;
-		return ticks1 < ticks2 ? -1 : 0;
+		return ticks1 > ticks2 ? 1 : ticks1 < ticks2 ? -1 : 0;
 	}
 
 	/// <summary>Compares the current object with another object of the same type.</summary>
@@ -378,4 +377,338 @@ public struct SYSTEMTIME : IEquatable<SYSTEMTIME>, IComparable<SYSTEMTIME>
 								((ulong)wMilliseconds & 0x3ff);
 
 	private static bool IsLeapYear(ushort year) => year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
+}
+
+/// <summary>
+/// Specifies a date and time, using individual members for the month, day, year, weekday, hour, minute, second, and millisecond. The
+/// time is either in coordinated universal time (UTC) or local time, depending on the function that is being called.
+/// </summary>
+[PInvokeData("winbase.h")]
+[StructLayout(LayoutKind.Sequential, Pack = 2)]
+public class PSYSTEMTIME : IEquatable<SYSTEMTIME>, IComparable<SYSTEMTIME>, IEquatable<PSYSTEMTIME>, IComparable<PSYSTEMTIME>
+{
+	private SYSTEMTIME st;
+
+	/// <summary>The year. The valid values for this member are 1601 through 30827.</summary>
+	public ushort wYear { get => st.wYear; set => st.wYear = value; }
+
+	/// <summary>
+	/// The month. This member can be one of the following values.
+	/// <list type="table">
+	/// <listheader>
+	/// <term>Value</term>
+	/// <term>Meaning</term>
+	/// </listheader>
+	/// <item>
+	/// <term>1</term>
+	/// <term>January</term>
+	/// </item>
+	/// <item>
+	/// <term>2</term>
+	/// <term>February</term>
+	/// </item>
+	/// <item>
+	/// <term>3</term>
+	/// <term>March</term>
+	/// </item>
+	/// <item>
+	/// <term>4</term>
+	/// <term>April</term>
+	/// </item>
+	/// <item>
+	/// <term>5</term>
+	/// <term>May</term>
+	/// </item>
+	/// <item>
+	/// <term>6</term>
+	/// <term>June</term>
+	/// </item>
+	/// <item>
+	/// <term>7</term>
+	/// <term>July</term>
+	/// </item>
+	/// <item>
+	/// <term>8</term>
+	/// <term>August</term>
+	/// </item>
+	/// <item>
+	/// <term>9</term>
+	/// <term>September</term>
+	/// </item>
+	/// <item>
+	/// <term>10</term>
+	/// <term>October</term>
+	/// </item>
+	/// <item>
+	/// <term>11</term>
+	/// <term>November</term>
+	/// </item>
+	/// <item>
+	/// <term>12</term>
+	/// <term>December</term>
+	/// </item>
+	/// </list>
+	/// </summary>
+	public ushort wMonth { get => st.wMonth; set => st.wMonth = value; }
+
+	/// <summary>
+	/// The day of the week. This member can be one of the following values.
+	/// <list type="table">
+	/// <listheader>
+	/// <term>Value</term>
+	/// <term>Meaning</term>
+	/// </listheader>
+	/// <item>
+	/// <term>0</term>
+	/// <term>Sunday</term>
+	/// </item>
+	/// <item>
+	/// <term>1</term>
+	/// <term>Monday</term>
+	/// </item>
+	/// <item>
+	/// <term>2</term>
+	/// <term>Tuesday</term>
+	/// </item>
+	/// <item>
+	/// <term>3</term>
+	/// <term>Wednesday</term>
+	/// </item>
+	/// <item>
+	/// <term>4</term>
+	/// <term>Thursday</term>
+	/// </item>
+	/// <item>
+	/// <term>5</term>
+	/// <term>Friday</term>
+	/// </item>
+	/// <item>
+	/// <term>6</term>
+	/// <term>Saturday</term>
+	/// </item>
+	/// </list>
+	/// </summary>
+	public ushort wDayOfWeek { get => st.wDayOfWeek; set => st.wDayOfWeek = value; }
+
+	/// <summary>The day of the month. The valid values for this member are 1 through 31.</summary>
+	public ushort wDay { get => st.wDay; set => st.wDay = value; }
+
+	/// <summary>The hour. The valid values for this member are 0 through 23.</summary>
+	public ushort wHour { get => st.wHour; set => st.wHour = value; }
+
+	/// <summary>The minute. The valid values for this member are 0 through 59.</summary>
+	public ushort wMinute { get => st.wMinute; set => st.wMinute = value; }
+
+	/// <summary>The second. The valid values for this member are 0 through 59.</summary>
+	public ushort wSecond { get => st.wSecond; set => st.wSecond = value; }
+
+	/// <summary>The millisecond. The valid values for this member are 0 through 999.</summary>
+	public ushort wMilliseconds { get => st.wMilliseconds; set => st.wMilliseconds = value; }
+
+	/// <summary>Initializes a new instance of the <see cref="SYSTEMTIME"/> struct with a <see cref="DateTime"/>.</summary>
+	/// <param name="dt">The <see cref="DateTime"/> value.</param>
+	/// <param name="toKind">Indicates whether the <see cref="SYSTEMTIME"/> should represent the local, universal or unknown time.</param>
+	/// <exception cref="ArgumentOutOfRangeException">dt - Year value must be 1601 through 30827</exception>
+	public PSYSTEMTIME(DateTime dt, DateTimeKind toKind = DateTimeKind.Unspecified) => st = new SYSTEMTIME(dt, toKind);
+
+	/// <summary>Initializes a new instance of the <see cref="SYSTEMTIME"/> struct.</summary>
+	/// <param name="year">The year. The valid values for this member are 1601 through 30827.</param>
+	/// <param name="month">
+	/// The month. This member can be one of the following values.
+	/// <list type="table">
+	/// <listheader>
+	/// <term>Value</term>
+	/// <term>Meaning</term>
+	/// </listheader>
+	/// <item>
+	/// <term>1</term>
+	/// <term>January</term>
+	/// </item>
+	/// <item>
+	/// <term>2</term>
+	/// <term>February</term>
+	/// </item>
+	/// <item>
+	/// <term>3</term>
+	/// <term>March</term>
+	/// </item>
+	/// <item>
+	/// <term>4</term>
+	/// <term>April</term>
+	/// </item>
+	/// <item>
+	/// <term>5</term>
+	/// <term>May</term>
+	/// </item>
+	/// <item>
+	/// <term>6</term>
+	/// <term>June</term>
+	/// </item>
+	/// <item>
+	/// <term>7</term>
+	/// <term>July</term>
+	/// </item>
+	/// <item>
+	/// <term>8</term>
+	/// <term>August</term>
+	/// </item>
+	/// <item>
+	/// <term>9</term>
+	/// <term>September</term>
+	/// </item>
+	/// <item>
+	/// <term>10</term>
+	/// <term>October</term>
+	/// </item>
+	/// <item>
+	/// <term>11</term>
+	/// <term>November</term>
+	/// </item>
+	/// <item>
+	/// <term>12</term>
+	/// <term>December</term>
+	/// </item>
+	/// </list>
+	/// </param>
+	/// <param name="day">The day of the month. The valid values for this member are 1 through 31.</param>
+	/// <param name="hour">The hour. The valid values for this member are 0 through 23.</param>
+	/// <param name="minute">The minute. The valid values for this member are 0 through 59.</param>
+	/// <param name="second">The second. The valid values for this member are 0 through 59.</param>
+	/// <param name="millisecond">The millisecond. The valid values for this member are 0 through 999.</param>
+	public PSYSTEMTIME(ushort year, ushort month, ushort day, ushort hour = 0, ushort minute = 0, ushort second = 0,
+		ushort millisecond = 0) => st = new SYSTEMTIME(year, month, day, hour, minute, second, millisecond);
+
+	/// <summary>Initializes a new instance of the <see cref="PSYSTEMTIME"/> class.</summary>
+	/// <param name="st">The <see cref="SYSTEMTIME"/> instance.</param>
+	public PSYSTEMTIME(SYSTEMTIME st) => this.st = st;
+
+	/// <summary>Gets or sets the day of the week.</summary>
+	/// <value>The day of the week.</value>
+	[ExcludeFromCodeCoverage]
+	public DayOfWeek DayOfWeek
+	{
+		get => st.DayOfWeek;
+		set => st.DayOfWeek = value;
+	}
+
+	/// <summary>Gets the number of ticks that represent the date and time of this instance.</summary>
+	public long Ticks => st.Ticks;
+
+	/// <summary>Indicates if two <see cref="PSYSTEMTIME"/> values are equal.</summary>
+	/// <param name="s1">The first <see cref="PSYSTEMTIME"/> value.</param>
+	/// <param name="s2">The second <see cref="PSYSTEMTIME"/> value.</param>
+	/// <returns><c>true</c> if both values are equal; otherwise <c>false</c>.</returns>
+	public static bool operator ==(PSYSTEMTIME? s1, PSYSTEMTIME? s2) => s1 is null ? s2 is null : s1.Equals(s2);
+
+	/// <summary>Indicates if two <see cref="PSYSTEMTIME"/> values are not equal.</summary>
+	/// <param name="s1">The first <see cref="PSYSTEMTIME"/> value.</param>
+	/// <param name="s2">The second <see cref="PSYSTEMTIME"/> value.</param>
+	/// <returns><c>true</c> if both values are not equal; otherwise <c>false</c>.</returns>
+	public static bool operator !=(PSYSTEMTIME? s1, PSYSTEMTIME? s2) => !(s1 == s2);
+
+	/// <summary>Determines whether one specified <see cref="PSYSTEMTIME"/> is greater than another specified <see cref="PSYSTEMTIME"/>.</summary>
+	/// <param name="s1">The first <see cref="PSYSTEMTIME"/> value.</param>
+	/// <param name="s2">The second <see cref="PSYSTEMTIME"/> value.</param>
+	/// <returns><c>true</c> if <paramref name="s1"/> is greater than <paramref name="s2"/>; otherwise, <c>false</c>.</returns>
+	public static bool operator >(PSYSTEMTIME? s1, PSYSTEMTIME? s2) => Compare(s1, s2) > 0;
+
+	/// <summary>Determines whether one specified <see cref="PSYSTEMTIME"/> is greater than or equal to another specified <see cref="PSYSTEMTIME"/>.</summary>
+	/// <param name="s1">The first <see cref="PSYSTEMTIME"/> value.</param>
+	/// <param name="s2">The second <see cref="PSYSTEMTIME"/> value.</param>
+	/// <returns><c>true</c> if <paramref name="s1"/> is greater than or equal to <paramref name="s2"/>; otherwise, <c>false</c>.</returns>
+	public static bool operator >=(PSYSTEMTIME? s1, PSYSTEMTIME? s2) => Compare(s1, s2) >= 0;
+
+	/// <summary>Determines whether one specified <see cref="PSYSTEMTIME"/> is less than another specified <see cref="PSYSTEMTIME"/>.</summary>
+	/// <param name="s1">The first <see cref="PSYSTEMTIME"/> value.</param>
+	/// <param name="s2">The second <see cref="PSYSTEMTIME"/> value.</param>
+	/// <returns><c>true</c> if <paramref name="s1"/> is less than <paramref name="s2"/>; otherwise, <c>false</c>.</returns>
+	public static bool operator <(PSYSTEMTIME? s1, PSYSTEMTIME? s2) => Compare(s1, s2) < 0;
+
+	/// <summary>Determines whether one specified <see cref="PSYSTEMTIME"/> is less than or equal to another specified <see cref="PSYSTEMTIME"/>.</summary>
+	/// <param name="s1">The first <see cref="PSYSTEMTIME"/> value.</param>
+	/// <param name="s2">The second <see cref="PSYSTEMTIME"/> value.</param>
+	/// <returns><c>true</c> if <paramref name="s1"/> is less than or equal to <paramref name="s2"/>; otherwise, <c>false</c>.</returns>
+	public static bool operator <=(PSYSTEMTIME? s1, PSYSTEMTIME? s2) => Compare(s1, s2) <= 0;
+
+	/// <summary>The minimum value supported by <see cref="PSYSTEMTIME"/>.</summary>
+	public static readonly PSYSTEMTIME MinValue = new(SYSTEMTIME.MinValue);
+
+	/// <summary>The maximum value supported by <see cref="PSYSTEMTIME"/>.</summary>
+	public static readonly PSYSTEMTIME MaxValue = new(SYSTEMTIME.MaxValue);
+
+	/// <summary>Performs an implicit conversion from <see cref="PSYSTEMTIME"/> to <see cref="SYSTEMTIME"/>.</summary>
+	/// <param name="st">The <see cref="PSYSTEMTIME"/> instance.</param>
+	/// <returns>The result of the conversion.</returns>
+	public static implicit operator SYSTEMTIME(PSYSTEMTIME? st) => st?.st ?? default;
+
+	/// <summary>Performs an implicit conversion from <see cref="SYSTEMTIME"/> to <see cref="PSYSTEMTIME"/>.</summary>
+	/// <param name="st">The <see cref="SYSTEMTIME"/> instance.</param>
+	/// <returns>The result of the conversion.</returns>
+	public static implicit operator PSYSTEMTIME(SYSTEMTIME st) => new(st);
+
+	/// <summary>Compares two instances of <see cref="PSYSTEMTIME"/> and returns an integer that indicates whether the first instance is earlier than, the same as, or later than the second instance.</summary>
+	/// <param name="s1">The first object to compare. </param>
+	/// <param name="s2">The second object to compare. </param>
+	/// <returns>A signed number indicating the relative values of t1 and t2.
+	/// <list type="table">
+	/// <listheader><term>Value Type</term><term>Condition</term></listheader>
+	/// <item><term>Less than zero</term><term>t1 is earlier than t2.</term></item>
+	/// <item><term>Zero</term><term>t1 is the same as t2.</term></item>
+	/// <item><term>Greater than zero</term><term>t1 is later than t2.</term></item>
+	/// </list>
+	///</returns>
+	public static int Compare(PSYSTEMTIME? s1, PSYSTEMTIME? s2) => s1 is null ? s2 is null ? 0 : -1 : s1.CompareTo(s2);
+
+	/// <summary>Compares the current object with another object of the same type.</summary>
+	/// <param name="other">An object to compare with this object.</param>
+	/// <returns>
+	/// A value that indicates the relative order of the objects being compared. The return value has the following meanings: Value
+	/// Meaning Less than zero This object is less than the <paramref name="other"/> parameter.Zero This object is equal to <paramref
+	/// name="other"/>. Greater than zero This object is greater than <paramref name="other"/>.
+	/// </returns>
+	public int CompareTo(PSYSTEMTIME? other) => other is null ? 1 : st.CompareTo(other.st);
+
+	/// <summary>Compares the current object with another object of the same type.</summary>
+	/// <param name="other">An object to compare with this object.</param>
+	/// <returns>
+	/// A value that indicates the relative order of the objects being compared. The return value has the following meanings: Value
+	/// Meaning Less than zero This object is less than the <paramref name="other"/> parameter.Zero This object is equal to <paramref
+	/// name="other"/>. Greater than zero This object is greater than <paramref name="other"/>.
+	/// </returns>
+	public int CompareTo(SYSTEMTIME other) => st.CompareTo(other);
+
+	/// <summary>Indicates whether the current object is equal to another object of the same type.</summary>
+	/// <param name="other">An object to compare with this object.</param>
+	/// <returns>true if the current object is equal to the <paramref name="other"/> parameter; otherwise, false.</returns>
+	public bool Equals(PSYSTEMTIME? other) => other is not null && (ReferenceEquals(this, other) || st.Equals(other.st));
+
+	/// <summary>Indicates whether the current object is equal to another object of the same type.</summary>
+	/// <param name="other">An object to compare with this object.</param>
+	/// <returns>true if the current object is equal to the <paramref name="other"/> parameter; otherwise, false.</returns>
+	public bool Equals(SYSTEMTIME other) => st.Equals(other);
+
+	/// <summary>Determines whether the specified <see cref="object"/>, is equal to this instance.</summary>
+	/// <param name="obj">The <see cref="object"/> to compare with this instance.</param>
+	/// <returns><c>true</c> if the specified <see cref="object"/> is equal to this instance; otherwise, <c>false</c>.</returns>
+	public override bool Equals(object? obj) => Equals(obj as PSYSTEMTIME);
+
+	/// <summary>Returns a hash code for this instance.</summary>
+	/// <returns>A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table.</returns>
+	public override int GetHashCode() => st.GetHashCode();
+
+	/// <summary>Converts this <see cref="SYSTEMTIME"/> instance to a <see cref="DateTime"/> instance.</summary>
+	/// <param name="kind">Indicates whether this <see cref="SYSTEMTIME"/> instance is local, universal or neither.</param>
+	/// <returns>An equivalent <see cref="DateTime"/> value.</returns>
+	public DateTime ToDateTime(DateTimeKind kind) => st.ToDateTime(kind);
+
+	/// <summary>Returns a <see cref="string"/> that represents this instance.</summary>
+	/// <returns>A <see cref="string"/> that represents this instance.</returns>
+	public override string ToString() => st.ToString();
+
+	/// <summary>Returns a <see cref="string" /> that represents this instance.</summary>
+	/// <param name="kind">One of the enumeration values that indicates whether the new object represents local time, UTC, or neither.</param>
+	/// <param name="format">A standard or custom date and time format string.</param>
+	/// <param name="provider">An object that supplies culture-specific formatting information.</param>
+	/// <returns>A <see cref="string" /> that represents this instance.</returns>
+	public string ToString(DateTimeKind kind, string? format, IFormatProvider? provider) => st.ToString(kind, format, provider);
 }

UnitTests/CSharpRunner/ImpersonateUser.cs

@@ -0,0 +1,23 @@
+using static Vanara.PInvoke.AdvApi32;
+
+namespace Vanara.PInvoke.Tests;
+
+public class ImpersonatedUser : IDisposable
+{
+	private readonly SafeHTOKEN hToken;
+
+	public ImpersonatedUser(string un, string pwd, string? svr = null)
+	{
+		if (!(svr?.StartsWith('\\') ?? false))
+			svr = $@"\\{svr}";
+		Win32Error.ThrowLastErrorIfFalse(LogonUser(un, svr, pwd, LogonUserType.LOGON32_LOGON_NETWORK, LogonUserProvider.LOGON32_PROVIDER_DEFAULT, out hToken));
+		Win32Error.ThrowLastErrorIfFalse(ImpersonateLoggedOnUser(hToken));
+	}
+
+	public void Dispose()
+	{
+		RevertToSelf();
+		((IDisposable)hToken).Dispose();
+		GC.SuppressFinalize(this);
+	}
+}

UnitTests/PInvoke/Printing/Printing.csproj

@@ -2,6 +2,9 @@
   <PropertyGroup>
     <AssemblyName>UnitTest.PInvoke.Printing</AssemblyName>
   </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="System.Drawing.Common" Version="7.0.0" />
+  </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\PInvoke\Kernel32\Vanara.PInvoke.Kernel32.csproj" />
     <ProjectReference Include="..\..\..\PInvoke\Printing\Vanara.PInvoke.Printing.csproj" />

UnitTests/PInvoke/Printing/PrintingTests.cs

@@ -11,13 +11,24 @@ namespace Vanara.PInvoke.Tests;
 [TestFixture]
 public class PrintingTests
 {
-	private const string connPtrName = "Foobar";
+	private string connPtrName = "";
+	private (string un, string pw, string sv) creds = ("", "", "");
 	private const string defKey = "PrinterDriverData";
 	private static readonly string defaultPrinterName = new System.Drawing.Printing.PrinterSettings().PrinterName;
+#pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
 	private SafeHPRINTER hprnt;
+#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
 
 	[OneTimeSetUp]
-	public void _Setup() => Assert.That(OpenPrinter(defaultPrinterName, out hprnt), ResultIs.Successful);
+	public void _Setup()
+	{
+		Assert.That(OpenPrinter(defaultPrinterName, out hprnt, new() { DesiredAccess = (uint)AccessRights.PRINTER_ACCESS_USE, pDatatype = "RAW", pDevMode = new DEVMODE() { dmDeviceName = defaultPrinterName } }), ResultIs.Successful);
+		var auth = (object[])TestCaseSources.GetAuthCasesFromFile(true, true)[0];
+		connPtrName = string.Concat(auth[5], '\\', auth[9]);
+		if (!connPtrName.StartsWith('\\'))
+			connPtrName = @"\\" + connPtrName;
+		creds = ((string)auth[6], (string)auth[7], (string)auth[5]);
+	}
 
 	[OneTimeTearDown]
 	public void _TearDown() => hprnt?.Dispose();
@@ -79,10 +90,10 @@ public class PrintingTests
 			pPrintProcessor = pi.pPrintProcessor,
 			Attributes = PRINTER_ATTRIBUTE.PRINTER_ATTRIBUTE_LOCAL
 		};
-		var p2 = new SafeHPRINTER(default, false);
+		SafeHPRINTER p2 = new(default, false);
+		Assert.That(p2 = AddPrinter(null, 2, pi2), ResultIs.ValidHandle);
 		try
 		{
-			Assert.That(p2 = AddPrinter(null, 2, pi2), ResultIs.ValidHandle);
 			GetSet("Test", 123, 123U);
 			GetSet("Test", 123L, 123UL);
 			GetSet("Test", "123");
@@ -102,9 +113,9 @@ public class PrintingTests
 			Assert.That(DeletePrinter(p2), ResultIs.Successful);
 		}
 
-		void GetSet(string vn, object v, object r = null, REG_VALUE_TYPE t = REG_VALUE_TYPE.REG_NONE)
+		void GetSet(string vn, object v, object? r = null, REG_VALUE_TYPE t = REG_VALUE_TYPE.REG_NONE)
 		{
-			if (r is null) r = v;
+			r ??= v;
 			Assert.That(SetPrinterData(p2, vn, v, t), ResultIs.Successful);
 			Assert.That(GetPrinterData(p2, vn), v.GetType().IsArray ? (IResolveConstraint)Is.EquivalentTo((IEnumerable)r) : Is.EqualTo(r));
 			Assert.That(DeletePrinterData(p2, vn), ResultIs.Successful);
@@ -248,20 +259,17 @@ public class PrintingTests
 	[Test]
 	public void EnumPrintersTest()
 	{
-		PRINTER_INFO_1[] res1;
-		Assert.That(res1 = EnumPrinters<PRINTER_INFO_1>().ToArray(), Is.Not.Empty);
-		TestContext.WriteLine(string.Join(",", res1.Select(v => v.pName)));
 		PRINTER_INFO_2[] res2;
 		Assert.That(res2 = EnumPrinters<PRINTER_INFO_2>().ToArray(), Is.Not.Empty);
-		TestContext.WriteLine(string.Join(",", res2.Select(v => v.Status)));
+		res2.WriteValues();
+		PRINTER_INFO_1[] res1;
+		Assert.That(res1 = EnumPrinters<PRINTER_INFO_1>().ToArray(), Is.Not.Empty);
 		//PRINTER_INFO_3[] res3;
 		//Assert.That(res3 = EnumPrinters<PRINTER_INFO_3>().ToArray(), Is.Not.Empty);
 		PRINTER_INFO_4[] res4;
 		Assert.That(res4 = EnumPrinters<PRINTER_INFO_4>().ToArray(), Is.Not.Empty);
-		TestContext.WriteLine(string.Join(",", res4.Select(v => v.Attributes)));
 		PRINTER_INFO_5[] res5;
 		Assert.That(res5 = EnumPrinters<PRINTER_INFO_5>().ToArray(), Is.Not.Empty);
-		TestContext.WriteLine(string.Join(",", res5.Select(v => v.pPortName)));
 		//PRINTER_INFO_6[] res6;
 		//Assert.That(res6 = EnumPrinters<PRINTER_INFO_6>().ToArray(), Is.Not.Empty);
 		//PRINTER_INFO_7[] res7;
@@ -381,14 +389,15 @@ public class PrintingTests
 		Assert.That(AddJob(hprnt, out var path, out var id), ResultIs.Successful);
 		try
 		{
-			System.IO.File.WriteAllText(path, "Test page.");
+			System.IO.File.WriteAllText(path!, "Test page.");
 
 			JOB_INFO_2 ji2 = default;
 			Assert.That(() => ji2 = GetJob<JOB_INFO_2>(hprnt, id), Throws.Nothing);
 			Assert.That(ji2.JobId, Is.EqualTo(id));
+			Assert.NotNull(ji2.pDatatype);
 			TestHelper.WriteValues(ji2);
 
-			var jobInfo = new JOB_INFO_1 { JobId = id, Priority = JOB_PRIORITY.MAX_PRIORITY, Status = ji2.Status, pDatatype = ji2.pDatatype };
+			var jobInfo = new JOB_INFO_1 { JobId = id, Priority = JOB_PRIORITY.MAX_PRIORITY, Status = ji2.Status, pDatatype = ji2.pDatatype! };
 			Assert.That(SetJob(hprnt, id, jobInfo), ResultIs.Successful);
 
 			Assert.That(ScheduleJob(hprnt, id), ResultIs.Successful);
@@ -432,7 +441,7 @@ public class PrintingTests
 		var bytes = new byte[] { 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 };
 		Kernel32.WriteFile(hspf, bytes, (uint)bytes.Length, out _);
 		Assert.That(CommitSpoolData(hprnt, hspf, (uint)bytes.Length), ResultIs.Successful);
-		Assert.That(() => hspf.Dispose(), Throws.Nothing);
+		Assert.That(hspf.Dispose, Throws.Nothing);
 	}
 
 	[Test]
@@ -474,7 +483,8 @@ public class PrintingTests
 					if (FindNextPrinterChangeNotification(hChange, out var chg, default, out var ppi) && !ppi.IsInvalid)
 					{
 						PRINTER_NOTIFY_INFO pi = ppi;
-						log.Add($"{chg}: {string.Join(",", pi.aData?.Select(d => d.Field))}");
+						if (pi.aData is not null)
+							log.Add($"{chg}: {string.Join(",", pi.aData.Select(d => d.Field))}");
 					}
 				}
 			}