From 44f0afe7325c09f6f55805b02a8dcbe3ebe6b428 Mon Sep 17 00:00:00 2001
From: dahall <dahall@byu.net>
Date: Wed, 28 Oct 2020 22:41:35 -0600
Subject: [PATCH] Added Vanara.Windows.Shell.StockIcon class

---
 Windows.Shell/StockIcon.cs | 122 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 Windows.Shell/StockIcon.cs

diff --git a/Windows.Shell/StockIcon.cs b/Windows.Shell/StockIcon.cs
new file mode 100644
index 00000000..ad350ff3
--- /dev/null
+++ b/Windows.Shell/StockIcon.cs
@@ -0,0 +1,122 @@
+using System;
+using System.Drawing;
+using Vanara.PInvoke;
+using static Vanara.PInvoke.Shell32;
+using static Vanara.PInvoke.User32;
+
+namespace Vanara.Windows.Shell
+{
+	/// <summary>Represents a standard system icon.</summary>
+	public class StockIcon : IDisposable
+	{
+		private SHGSI curFlags;
+		private SHSTOCKICONID curId;
+		private HICON hIcon;
+		private IconLocation location;
+		private int systemImageIndex;
+
+		static StockIcon() => FileIconInit(false);
+
+		/// <summary>Creates a new StockIcon instance with the specified identifer and options.</summary>
+		/// <param name="id">A value that identifies the icon represented by this instance.</param>
+		/// <param name="size">A value that indicates the size of the stock icon.</param>
+		/// <param name="isLinkOverlay">A bool value that indicates whether the icon has a link overlay.</param>
+		/// <param name="isSelected">A bool value that indicates whether the icon is in a selected state.</param>
+		public StockIcon(SHSTOCKICONID id, ShellIconType size = ShellIconType.Large, bool isLinkOverlay = false, bool isSelected = false)
+		{
+			Identifier = id;
+			LinkOverlay = isLinkOverlay;
+			Selected = isSelected;
+			Size = size;
+		}
+
+		/// <summary>Finalizes an instance of the <see cref="StockIcon"/> class.</summary>
+		~StockIcon()
+		{
+			Dispose(false);
+		}
+
+		/// <summary>Gets the icon image in <see cref="System.Drawing.Bitmap"/> format.</summary>
+		public Bitmap Bitmap { get { Refresh(); return hIcon.IsNull ? null : Bitmap.FromHicon((IntPtr)hIcon); } }
+
+		/// <summary>Gets the icon image in <see cref="System.Drawing.Icon"/> format.</summary>
+		public Icon Icon { get { Refresh(); return hIcon.IsNull ? null : Icon.FromHandle((IntPtr)hIcon); } }
+
+		/// <summary>Gets or sets the Stock Icon identifier associated with this icon.</summary>
+		public SHSTOCKICONID Identifier { get; set; }
+
+		/// <summary>Gets or sets a value that cotrols whether to put a link overlay on the icon.</summary>
+		/// <value>A <see cref="bool"/> value.</value>
+		public bool LinkOverlay { get; set; }
+
+		/// <summary>Gets the icon location, composed of a resource path and the icon's index.</summary>
+		/// <value>The icon location.</value>
+		public IconLocation Location { get { Refresh(); return location; } }
+
+		/// <summary>Gets or sets a value indicating whether the icon appears selected.</summary>
+		/// <value>A <see cref="bool"/> value.</value>
+		public bool Selected { get; set; }
+
+		/// <summary>Gets or sets a value that controls the size of the Stock Icon.</summary>
+		/// <value>A <see cref="ShellIconType"/> value.</value>
+		public ShellIconType Size { get; set; }
+
+		/// <summary>Gets the index of the image in the system icon cache.</summary>
+		/// <value>The index of the system image.</value>
+		public int SystemImageIndex { get { Refresh(); return systemImageIndex; } }
+
+		/// <summary>Release the native objects</summary>
+		public void Dispose()
+		{
+			Dispose(true);
+			System.GC.SuppressFinalize(this);
+		}
+
+		/// <summary>Release the native and managed objects</summary>
+		/// <param name="disposing">Indicates that this is being called from Dispose(), rather than the finalizer.</param>
+		protected virtual void Dispose(bool disposing)
+		{
+			if (disposing)
+			{
+				// dispose managed resources here
+			}
+
+			// Unmanaged resources
+			if (hIcon != IntPtr.Zero)
+				DestroyIcon(hIcon);
+		}
+
+		private SHGSI GetFlags() => SHGSI.SHGSI_ICON | SHGSI.SHGSI_ICONLOCATION | SHGSI.SHGSI_SYSICONINDEX | (SHGSI)Size | (Selected ? SHGSI.SHGSI_SELECTED : 0) | (LinkOverlay ? SHGSI.SHGSI_LINKOVERLAY : 0);
+
+		private void Refresh()
+		{
+			var flags = GetFlags();
+			if (curFlags == flags && curId == Identifier)
+				return;
+
+			if (hIcon != IntPtr.Zero)
+			{
+				DestroyIcon(hIcon);
+				hIcon = default;
+			}
+
+			var info = SHSTOCKICONINFO.Default;
+			var hr = SHGetStockIconInfo(curId = Identifier, curFlags = flags, ref info);
+
+			// If we get an error, return null as the icon requested might not be supported on the current system
+			if (hr == HRESULT.E_INVALIDARG)
+				throw new InvalidOperationException("Invalid identifier.");
+			else if (hr.Succeeded)
+			{
+				hIcon = info.hIcon;
+				location = new IconLocation(info.szPath, info.iIcon);
+				systemImageIndex = info.iSysImageIndex;
+			}
+			else
+			{
+				location = null;
+				systemImageIndex = 0;
+			}
+		}
+	}
+}
\ No newline at end of file