Using IList for Insert/Add of items if implemented. This fixes so collections inside System.Windows.Input namespace is synchronized with SD internal collection when undo/redo operations have executed on the collection.

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Tests/Designer/ModelTests.cs

@@ -320,6 +320,63 @@ namespace ICSharpCode.WpfDesign.Tests.Designer
 			AssertLog("");
 		}
 		
+		[Test]
+		public void UndoRedoInputBindings()
+		{
+			DesignItem textBlock = CreateCanvasContext("<TextBlock/>");
+			UndoService s = textBlock.Context.Services.GetService<UndoService>();
+			IComponentService component = textBlock.Context.Services.Component;
+			
+			Assert.IsFalse(s.CanUndo);
+			Assert.IsFalse(s.CanRedo);
+			
+			DesignItemProperty inputbinding = textBlock.Properties["InputBindings"];
+			Assert.IsTrue(inputbinding.IsCollection);
+			
+			const string expectedXaml = @"<TextBlock>
+  <TextBlock.InputBindings>
+    <MouseBinding Gesture=""LeftDoubleClick"" Command=""ApplicationCommands.New"" />
+  </TextBlock.InputBindings>
+</TextBlock>";
+			
+			using (ChangeGroup changeGroup = textBlock.Context.OpenGroup("", new[] { textBlock }))
+			{
+				DesignItem di = component.RegisterComponentForDesigner(new System.Windows.Input.MouseBinding());
+				di.Properties["Gesture"].SetValue(System.Windows.Input.MouseAction.LeftDoubleClick);
+				di.Properties["Command"].SetValue("ApplicationCommands.New");
+
+				inputbinding.CollectionElements.Add(di);
+
+				changeGroup.Commit();
+			}
+			
+			Assert.IsTrue(s.CanUndo);
+			Assert.IsFalse(s.CanRedo);
+			AssertCanvasDesignerOutput(expectedXaml, textBlock.Context);
+			
+			inputbinding = textBlock.Properties["InputBindings"];
+			Assert.IsTrue(((System.Windows.Input.InputBindingCollection)inputbinding.ValueOnInstance).Count == inputbinding.CollectionElements.Count);
+			
+			const string undoXaml = @"<TextBlock>
+  <TextBlock.InputBindings>
+  </TextBlock.InputBindings>
+</TextBlock>";
+			
+			s.Undo();
+			Assert.IsFalse(s.CanUndo);
+			Assert.IsTrue(s.CanRedo);
+			AssertCanvasDesignerOutput(undoXaml, textBlock.Context);
+			
+			s.Redo();
+			Assert.IsTrue(s.CanUndo);
+			Assert.IsFalse(s.CanRedo);
+			AssertCanvasDesignerOutput(expectedXaml, textBlock.Context);
+			
+			Assert.IsTrue(((System.Windows.Input.InputBindingCollection)inputbinding.ValueOnInstance).Count == inputbinding.CollectionElements.Count);
+			
+			AssertLog("");
+		}
+		
 		[Test]
 		public void AddTextBoxToCanvas()
 		{

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Tests/XamlDom/CollectionTests.cs

@@ -20,5 +20,55 @@ namespace ICSharpCode.WpfDesign.Tests.XamlDom
 
             Assert.IsFalse(isCollection);
         }
+        
+        /// <summary>
+        /// This test is here do demonstrate a peculiarity (or bug) with collections inside System.Windows.Input namespace.
+        /// The problem is that inserting the first item into the collection will silently fail (Count still 0 after Insert), first item must use Add method.
+        /// </summary>
+        [Test]
+		public void InputCollectionsPeculiarityOrBug()
+		{
+			// InputBindingCollection START
+			var inputBindingCollection = new System.Windows.Input.InputBindingCollection();
+			
+			// NOTE: this silently fails (Count is 0 after insert)
+			inputBindingCollection.Insert(0, new System.Windows.Input.MouseBinding());
+			Assert.IsTrue(inputBindingCollection.Count == 0);
+			
+			inputBindingCollection.Add(new System.Windows.Input.MouseBinding());
+			Assert.IsTrue(inputBindingCollection.Count == 1);
+			
+			inputBindingCollection.Insert(0, new System.Windows.Input.MouseBinding());
+			Assert.IsTrue(inputBindingCollection.Count == 2);
+			// InputBindingCollection END
+			
+			// CommandBindingCollection START
+			var commandBindingCollection = new System.Windows.Input.CommandBindingCollection();
+			
+			// NOTE: this silently fails (Count is 0 after insert)
+			commandBindingCollection.Insert(0, new System.Windows.Input.CommandBinding());
+			Assert.IsTrue(commandBindingCollection.Count == 0);
+			
+			commandBindingCollection.Add(new System.Windows.Input.CommandBinding());
+			Assert.IsTrue(commandBindingCollection.Count == 1);
+			
+			commandBindingCollection.Insert(0, new System.Windows.Input.CommandBinding());
+			Assert.IsTrue(commandBindingCollection.Count == 2);
+			// CommandBindingCollection END
+			
+			// List START (how it probably should work...)
+			var list = new List<string>();
+			
+			// NOTE: this is successful for ordinary List<T>
+			list.Insert(0, "A");
+			Assert.IsTrue(list.Count == 1);
+			
+			list.Add("A");
+			Assert.IsTrue(list.Count == 2);
+			
+			list.Insert(0, "A");
+			Assert.IsTrue(list.Count == 3);
+			// List END
+		}
     }
 }

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.XamlDom/Project/CollectionSupport.cs

@@ -107,11 +107,27 @@ namespace ICSharpCode.WpfDesign.XamlDom
 		/// </summary>
 		public static void Insert(Type collectionType, object collectionInstance, XamlPropertyValue newElement, int index)
 		{
-			collectionType.InvokeMember(
-				"Insert", BindingFlags.Public | BindingFlags.InvokeMethod | BindingFlags.Instance,
-				null, collectionInstance,
-				new object[] { index, newElement.GetValueFor(null) },
-				CultureInfo.InvariantCulture);
+			object value = newElement.GetValueFor(null);
+			
+			// Using IList, with possible Add instead of Insert, was primarily added as a workaround
+			// for a peculiarity (or bug) with collections inside System.Windows.Input namespace.
+			// See CollectionTests.InputCollectionsPeculiarityOrBug test method for details.
+			var list = collectionInstance as IList;
+			if (list != null) {
+				if (list.Count == index) {
+					list.Add(value);
+				}
+				else {
+					list.Insert(index, value);
+				}
+			}
+			else {
+				collectionType.InvokeMember(
+					"Insert", BindingFlags.Public | BindingFlags.InvokeMethod | BindingFlags.Instance,
+					null, collectionInstance,
+					new object[] { index, value },
+					CultureInfo.InvariantCulture);
+			}
 		}
 		
 		/// <summary>