chore: Build issue fixes

src/Uno.UI.Runtime.Skia.Wpf/WpfHost.cs

@@ -366,3 +366,4 @@ private void InvalidateOverlays()
 		WpfCanvas? IWpfHost.NativeOverlayLayer => NativeOverlayLayer;
 	}
 }
+DesktopWindowXamlSource

src/Uno.UI.XamlHost/IXamlMetadataContainer.cs

@@ -1,4 +1,9 @@
-using System.Collections.Generic;
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+// https://github.com/CommunityToolkit/Microsoft.Toolkit.Win32/blob/master/Microsoft.Toolkit.Win32.UI.XamlApplication/XamlApplication.idl
+
+using System.Collections.Generic;
 using Windows.UI.Xaml.Markup;
 
 namespace Uno.UI.XamlHost;

src/Uno.UI.XamlHost/MetadataProviderDiscovery.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
+// https://github.com/CommunityToolkit/Microsoft.Toolkit.Win32/blob/master/Microsoft.Toolkit.Win32.UI.XamlHost/MetadataProviderDiscovery.cs
 
 using System;
 using System.Collections.Generic;
@@ -14,7 +15,7 @@ namespace Uno.UI.XamlHost;
 
 /// <summary>
 /// MetadataProviderDiscovery is responsible for loading all metadata providers for custom UWP XAML
-/// types.  In this implementation, reflection is used at runtime to probe for metadata providers in
+/// types. In this implementation, reflection is used at runtime to probe for metadata providers in
 /// the working directory, allowing any type that includes metadata (compiled in to a .NET framework
 /// assembly) to be used without explicit metadata handling by the application developer.  This
 /// internal class will be amended or removed when additional type loading support is available.
@@ -59,11 +60,12 @@ internal static class MetadataProviderDiscovery
 			{
 				yield return provider;
 
-				if (typeof(WUX.Application).IsAssignableFrom(provider.GetType()))
-				{
-					System.Diagnostics.Debug.WriteLine("Xaml application has been created");
-					yield break;
-				}
+				// TODO: Yield break is weird here, investigate in WCT issues. #8978
+				//if (typeof(WUX.Application).IsAssignableFrom(provider.GetType()))
+				//{
+				//	System.Diagnostics.Debug.WriteLine("Xaml application has been created");
+				//	yield break;
+				//}
 			}
 		}
 	}

src/Uno.UI.XamlHost/UnoTypeFactory.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
+// https://github.com/CommunityToolkit/Microsoft.Toolkit.Win32/blob/master/Microsoft.Toolkit.Win32.UI.XamlHost/UWPTypeFactory.cs
 
 using System;
 using windows = Windows;

src/Uno.UI.XamlHost/XamlApplication.cs

@@ -1,4 +1,9 @@
-using System;
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+// https://github.com/CommunityToolkit/Microsoft.Toolkit.Win32/blob/master/Microsoft.Toolkit.Win32.UI.XamlApplication/XamlApplication.cpp
+
+using System;
 using System.Collections.Generic;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Markup;

src/Uno.UI.XamlHost/XamlApplicationExtensions.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
+// https://github.com/CommunityToolkit/Microsoft.Toolkit.Win32/blob/master/Microsoft.Toolkit.Win32.UI.XamlHost/XamlApplicationExtensions.cs
 
 using System;
 using System.Linq;

src/Uno.UI/UI/Xaml/Hosting/DesktopWindowXamlSource.cs

@@ -1,7 +1,10 @@
-using System;
+#pragma warning disable 67 // TODO: Focus-related members are currently unused #8978
+
+using System;
 using Uno.UI.Xaml.Core;
 using Uno.UI.Xaml.Islands;
 using Windows.Foundation;
+using WinUICoreServices = global::Uno.UI.Xaml.Core.CoreServices;
 
 namespace Windows.UI.Xaml.Hosting;
 
@@ -50,16 +53,17 @@ public UIElement Content
 		{
 			if (_root is null)
 			{
-				_root = new XamlIslandRoot(CoreServices.Instance);
+				_root = new XamlIslandRoot(WinUICoreServices.Instance);
 			}
 
 			_root.SetPublicRootVisual(value);
 
-			UIElement.LoadingRootElement(_root);
-			UIElement.RootElementLoaded(_root);
+			OnContentChangedPartial(_root);
 		}
 	}
 
+	partial void OnContentChangedPartial(XamlIslandRoot xamlIslandRoot);
+
 	/// <summary>
 	/// Attempts to programmatically give focus to the DesktopWindowXamlSource in the desktop application.
 	/// </summary>

src/Uno.UI/UI/Xaml/Hosting/DesktopWindowXamlSource.netstd.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Uno.UI.Xaml.Islands;
+
+namespace Windows.UI.Xaml.Hosting;
+
+partial class DesktopWindowXamlSource
+{
+	partial void OnContentChangedPartial(XamlIslandRoot xamlIslandRoot)
+	{
+		// Ensure the root element of the XamlIsland is loaded.
+		UIElement.LoadingRootElement(_root);
+		UIElement.RootElementLoaded(_root);
+	}
+}

src/Uno.UI/UI/Xaml/Internal/InputManager.Pointers.Managed.cs

@@ -48,7 +48,7 @@ internal void SetPointerCapture(PointerIdentifier identifier)
 	internal void ReleasePointerCapture(PointerIdentifier identifier)
 		=> _pointerManager.SetPointerCapture(identifier);
 
-	private PointerManager _pointerManager;
+	private PointerManager _pointerManager = null!;
 
 	partial void InitializeManagedPointers()
 	{

src/Uno.UI/UI/Xaml/Internal/Islands/XamlIslandRoot.cs

@@ -3,15 +3,15 @@
 using Windows.UI;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
-using CoreServices = global::Uno.UI.Xaml.Core.CoreServices;
+using WinUICoreServices = global::Uno.UI.Xaml.Core.CoreServices;
 
 namespace Uno.UI.Xaml.Islands;
 
 internal partial class XamlIslandRoot : Panel
 {
 	private readonly ContentRoot _contentRoot;
 
-	internal XamlIslandRoot(CoreServices coreServices)
+	internal XamlIslandRoot(WinUICoreServices coreServices)
 	{
 		_contentRoot = coreServices.ContentRootCoordinator.CreateContentRoot(ContentRootType.XamlIsland, Colors.Transparent, this);
 

src/Uno.UI/UI/Xaml/UIElement.Layout.netstd.cs

@@ -43,7 +43,11 @@ public void InvalidateMeasure()
 				(this.GetParent() as UIElement)?.InvalidateMeasure();
 				if (IsVisualTreeRoot)
 				{
+#if __SKIA__
 					XamlRoot.InvalidateMeasure();
+#else
+					Window.InvalidateMeasure();
+#endif
 				}
 			}
 		}
@@ -70,7 +74,11 @@ internal void InvalidateParentMeasureDirtyPath()
 			}
 			else if (IsVisualTreeRoot)
 			{
+#if __SKIA__
 				XamlRoot.InvalidateMeasure();
+#else
+				Window.InvalidateMeasure();
+#endif
 			}
 		}
 
@@ -97,7 +105,11 @@ public void InvalidateArrange()
 				(this.GetParent() as UIElement)?.InvalidateArrange();
 				if (IsVisualTreeRoot)
 				{
+#if __SKIA__
 					XamlRoot.InvalidateArrange();
+#else
+					Window.InvalidateArrange();
+#endif
 				}
 			}
 		}
@@ -124,7 +136,11 @@ private void InvalidateParentArrangeDirtyPath()
 			}
 			else //TODO: Why not check IsVisualTreeRoot as in InvalidateParentMeasureDirtyPath?
 			{
+#if __SKIA__
 				XamlRoot?.InvalidateArrange();
+#else
+				Window.InvalidateArrange();
+#endif
 			}
 		}