Added improved registry key closing to registration classes

Windows.Shell/Registration/FileTypeAssociation.cs

@@ -11,7 +11,8 @@ namespace Vanara.Windows.Shell.Registration
 		internal FileTypeAssociation(string ext, RegistryKey key, bool readOnly) : base(key, readOnly)
 		{
 			Extension = ext;
-			OpenWithProgIds = new RegBasedKeyCollection(key.OpenSubKey("OpenWithProgIds", !readOnly), readOnly);
+			var owpi = readOnly ? key.OpenSubKey("OpenWithProgIds", false) : key.CreateSubKey("OpenWithProgIds", RegistryKeyPermissionCheck.ReadWriteSubTree);
+			OpenWithProgIds = new RegBasedKeyCollection(owpi, readOnly);
 		}
 
 		/// <summary>Gets or sets the Content Type value to the file type's MIME content type.</summary>
@@ -120,8 +121,8 @@ namespace Vanara.Windows.Shell.Registration
 		{
 			if (extension is null) throw new ArgumentNullException(nameof(extension));
 			if (!extension.StartsWith(".")) throw new ArgumentException("The value must be in the format \".ext\"", nameof(extension));
-			using var sk = ShellRegistrar.GetRoot(systemWide, true);
+			using (var sk = ShellRegistrar.GetRoot(systemWide, true))
-			try { sk.DeleteSubKeyTree(extension); } catch { sk.DeleteSubKey(extension, false); }
+				try { sk.DeleteSubKeyTree(extension); } catch { sk.DeleteSubKey(extension, false); }
 			ShellRegistrar.NotifyShell();
 		}
 

Windows.Shell/Registration/ProgId.cs

@@ -292,8 +292,10 @@ namespace Vanara.Windows.Shell
 			using var root = ShellRegistrar.GetRoot(systemWide, false);
 			foreach (var ext in root.GetSubKeyNames().Where(ext => ext.StartsWith(".")))
 			{
-				using var openWithKey = root.OpenSubKey(Path.Combine(ext, OpenWithProgIds));
+				var hasValue = false;
-				if (openWithKey?.HasValue(progId) == true)
+				using (var openWithKey = root.OpenSubKey(Path.Combine(ext, OpenWithProgIds)))
+					hasValue = openWithKey?.HasValue(progId) ?? false;
+				if (hasValue)
 					yield return ext;
 			}
 		}
@@ -332,7 +334,8 @@ namespace Vanara.Windows.Shell
 		public void Add(string ext)
 		{
 			EnsureWritable();
-			FileTypeAssociation.Register(ext, IsSystemWide).OpenWithProgIds.Add(progId);
+			using var assoc = FileTypeAssociation.Register(ext, IsSystemWide);
+			assoc.OpenWithProgIds.Add(progId);
 		}
 
 		/// <summary>Clears this instance.</summary>

Windows.Shell/Registration/RegBasedKeyCollection.cs

@@ -8,7 +8,7 @@ namespace Vanara.Windows.Shell.Registration
 {
 	/// <summary>A collection of values under a key that is treated as a collection of strings.</summary>
 	/// <seealso cref="System.Collections.Generic.ICollection{T}"/>
-	internal class RegBasedKeyCollection : ICollection<string>
+	internal class RegBasedKeyCollection : ICollection<string>, IDisposable
 	{
 		/// <summary>The base key from which to perform all queries.</summary>
 		protected internal RegistryKey key;
@@ -18,13 +18,14 @@ namespace Vanara.Windows.Shell.Registration
 		/// <param name="readOnly">if set to <c>true</c> the supplied <paramref name="key"/> was opened read-only.</param>
 		protected internal RegBasedKeyCollection(RegistryKey key, bool readOnly)
 		{
-			this.key = key ?? throw new ArgumentNullException(nameof(key));
+			if (key is null && !readOnly) throw new ArgumentNullException(nameof(key));
+			this.key = key;
 			IsReadOnly = readOnly;
 		}
 
 		/// <summary>Gets the count.</summary>
 		/// <value>The count.</value>
-		public int Count => key.ValueCount;
+		public int Count => key?.ValueCount ?? 0;
 
 		/// <summary>Gets or sets a value indicating whether these settings are read-only.</summary>
 		public bool IsReadOnly { get; }
@@ -34,21 +35,24 @@ namespace Vanara.Windows.Shell.Registration
 		public void Add(string item) { EnsureWritable(); key.SetValue(item, string.Empty, RegistryValueKind.String); }
 
 		/// <summary>Clears this instance.</summary>
-		public void Clear() => key.DeleteAllSubItems();
+		public void Clear() { EnsureWritable(); key.DeleteAllSubItems(); }
 
 		/// <summary>Determines whether this instance contains the object.</summary>
 		/// <param name="item">The item.</param>
 		/// <returns><see langword="true"/> if [contains] [the specified item]; otherwise, <see langword="false"/>.</returns>
-		public bool Contains(string item) => key.HasValue(item);
+		public bool Contains(string item) => key?.HasValue(item) ?? false;
 
 		/// <summary>Copies to.</summary>
 		/// <param name="array">The array.</param>
 		/// <param name="arrayIndex">Index of the array.</param>
-		public void CopyTo(string[] array, int arrayIndex) => Array.Copy(key.GetValueNames(), 0, array, arrayIndex, Count);
+		public void CopyTo(string[] array, int arrayIndex) { if (key != null) Array.Copy(key.GetValueNames(), 0, array, arrayIndex, Count); }
+
+		/// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
+		public void Dispose() => key?.Close();
 
 		/// <summary>Gets the enumerator.</summary>
 		/// <returns></returns>
-		public IEnumerator<string> GetEnumerator() => key.GetValueNames().Cast<string>().GetEnumerator();
+		public IEnumerator<string> GetEnumerator() => (key?.GetValueNames().Cast<string>() ?? new string[0]).GetEnumerator();
 
 		/// <summary>Removes the specified item.</summary>
 		/// <param name="item">The item.</param>