feat: Moving navigation to background thread

src/Uno.Extensions.Core/IDispatcher.cs

@@ -10,4 +10,9 @@ public interface IDispatcher
 	/// <param name="cancellation">An cancellation token to cancel the async operation.</param>
 	/// <returns>A ValueTask to asynchronously get the result of the operation.</returns>
 	ValueTask<TResult> ExecuteAsync<TResult>(AsyncFunc<TResult> func, CancellationToken cancellation);
+
+	/// <summary>
+	///  Gets a value that specifies whether the current execution context is on the UI thread.
+	/// </summary>
+	bool HasThreadAccess { get; }
 }

src/Uno.Extensions.Core/PlatformHelper.cs

@@ -1,6 +1,6 @@
 namespace Uno.Extensions;
 
-public class PlatformHelper
+public static class PlatformHelper
 {
 	private static bool _isNetCore;
 	private static bool _initialized;

src/Uno.Extensions.Navigation.UI/Dispatcher.cs

@@ -33,5 +33,15 @@ public Dispatcher(FrameworkElement element)
 
 	/// <inheritdoc />
 	public async ValueTask<TResult> ExecuteAsync<TResult>(AsyncFunc<TResult> func, CancellationToken cancellation)
-		=> await _dispatcher.ExecuteAsync(func, cancellation);
+	{
+		if (!PlatformHelper.IsWebAssembly && // Assume for web that we always call executeasync on dispatcher
+			HasThreadAccess)
+		{
+			return await func(cancellation);
+		}
+		return await _dispatcher.ExecuteAsync(func, cancellation);
+	}
+
+	/// <inheritdoc />
+	public bool HasThreadAccess => _dispatcher.HasThreadAccess;
 }

src/Uno.Extensions.Navigation.UI/Navigator.cs

@@ -45,6 +45,15 @@ protected Navigator(
 		var regionUpdateId = RouteUpdater?.StartNavigation(Region) ?? Guid.Empty;
 		try
 		{
+
+			if (Dispatcher.HasThreadAccess &&
+				!request.InProgress)
+			{
+				request = request with { InProgress = true }; // Prevent multiple re-entrance where HasThreadAccess always returns true eg WASM
+				if (Logger.IsEnabled(LogLevel.Information)) Logger.LogInformationMessage($"Navigation started on UI thread, so moving to background thread");
+				return await Task.Run(() => NavigateAsync(request));
+			}
+
 			if (request.Source is null)
 			{
 				if (Logger.IsEnabled(LogLevel.Information)) Logger.LogInformationMessage($"Starting Navigation - Navigator: {this.GetType().Name} Request: {request.Route}");

src/Uno.Extensions.Navigation.UI/Navigators/PanelVisiblityNavigator.cs

@@ -99,27 +99,28 @@ protected override async Task<bool> RegionCanNavigate(Route route, RouteInfo? ro
 		return path;
 	}
 
-	protected override Task PostNavigateAsync()
+	protected override async Task PostNavigateAsync()
 	{
 		if (Control is not null)
 		{
-			foreach (var child in Control.Children.OfType<FrameworkElement>())
+			await Dispatcher.ExecuteAsync(async cancellation =>
 			{
-				if(child == CurrentlyVisibleControl)
+				foreach (var child in Control.Children.OfType<FrameworkElement>())
 				{
-					child.Opacity = 1;
-					child.Visibility = Visibility.Visible;
-				}
-				else
-				{
-					child.Opacity = 0;
-					child.Visibility = Visibility.Collapsed;
+					if (child == CurrentlyVisibleControl)
+					{
+						child.Opacity = 1;
+						child.Visibility = Visibility.Visible;
+					}
+					else
+					{
+						child.Opacity = 0;
+						child.Visibility = Visibility.Collapsed;
 
+					}
 				}
-			}
+			});
 		}
-
-		return Task.CompletedTask;
 	}
 
 	private FrameworkElement? FindByPath(string? path)

src/Uno.Extensions.Navigation/NavigationRequest.cs

@@ -4,6 +4,8 @@
 public record NavigationRequest(object Sender, Route Route, CancellationToken? Cancellation = default, Type? Result = null, INavigator? Source = null)
 #pragma warning restore SA1313 // Parameter names should begin with lower-case letter
 {
+	internal bool InProgress { get; init; }
+
 	public override string ToString() => $"Request [Sender: {Sender.GetType().Name}, Route:{Route}, Result: {Result?.Name ?? "N/A"}]";
 
 	internal virtual IResponseNavigator? GetResponseNavigator(IResponseNavigatorFactory responseFactory, INavigator navigator) => default;

testing/TestHarness/Directory.Build.targets

@@ -34,4 +34,9 @@
   </Choose>
 
 	<Import Project="..\..\src\xamarinmac-workaround.targets" Condition="exists('..\..\src\xamarinmac-workaround.targets') and $(TargetFramework.ToLower().StartsWith('xamarin')) and $(TargetFramework.ToLower().Contains('mac'))" />
+
+	<!-- Uno.WinUI.MSAL references Uno.WinUI for windows10 tfm. This target
+		overrides the protection in uno.winui.targets that raises an error 
+		that breaks build -->
+	<Target Name="_WinAppSDKNotSupported" BeforeTargets="BeforeBuild" />
 </Project>

testing/TestHarness/TestHarness-ui.slnf

@@ -8,15 +8,16 @@
       "..\\..\\src\\Uno.Extensions.Authentication.UI\\Uno.Extensions.Authentication.UI.csproj",
       "..\\..\\src\\Uno.Extensions.Authentication\\Uno.Extensions.Authentication.csproj",
       "..\\..\\src\\Uno.Extensions.Configuration\\Uno.Extensions.Configuration.csproj",
+      "..\\..\\src\\Uno.Extensions.Core.Generators\\Uno.Extensions.Core.Generators.csproj",
       "..\\..\\src\\Uno.Extensions.Core\\Uno.Extensions.Core.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting.UI\\Uno.Extensions.Hosting.UWP.Skia.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting.UI\\Uno.Extensions.Hosting.UWP.Wasm.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting.UI\\Uno.Extensions.Hosting.UWP.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting\\Uno.Extensions.Hosting.csproj",
       "..\\..\\src\\Uno.Extensions.Http.Refit\\Uno.Extensions.Http.Refit.csproj",
       "..\\..\\src\\Uno.Extensions.Http\\Uno.Extensions.Http.csproj",
-      "..\\..\\src\\Uno.Extensions.Localization\\Uno.Extensions.Localization.csproj",
       "..\\..\\src\\Uno.Extensions.Localization.UI\\Uno.Extensions.Localization.UI.csproj",
+      "..\\..\\src\\Uno.Extensions.Localization\\Uno.Extensions.Localization.csproj",
       "..\\..\\src\\Uno.Extensions.Logging.Serilog\\Uno.Extensions.Logging.Serilog.csproj",
       "..\\..\\src\\Uno.Extensions.Logging\\Uno.Extensions.Logging.UWP.Skia.csproj",
       "..\\..\\src\\Uno.Extensions.Logging\\Uno.Extensions.Logging.UWP.Wasm.csproj",

testing/TestHarness/TestHarness-winui.slnf

@@ -8,15 +8,16 @@
       "..\\..\\src\\Uno.Extensions.Authentication.UI\\Uno.Extensions.Authentication.WinUI.csproj",
       "..\\..\\src\\Uno.Extensions.Authentication\\Uno.Extensions.Authentication.csproj",
       "..\\..\\src\\Uno.Extensions.Configuration\\Uno.Extensions.Configuration.csproj",
+      "..\\..\\src\\Uno.Extensions.Core.Generators\\Uno.Extensions.Core.Generators.csproj",
       "..\\..\\src\\Uno.Extensions.Core\\Uno.Extensions.Core.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting.UI\\Uno.Extensions.Hosting.WinUI.Skia.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting.UI\\Uno.Extensions.Hosting.WinUI.Wasm.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting.UI\\Uno.Extensions.Hosting.WinUI.csproj",
       "..\\..\\src\\Uno.Extensions.Hosting\\Uno.Extensions.Hosting.csproj",
       "..\\..\\src\\Uno.Extensions.Http.Refit\\Uno.Extensions.Http.Refit.csproj",
       "..\\..\\src\\Uno.Extensions.Http\\Uno.Extensions.Http.csproj",
-      "..\\..\\src\\Uno.Extensions.Localization\\Uno.Extensions.Localization.csproj",
       "..\\..\\src\\Uno.Extensions.Localization.UI\\Uno.Extensions.Localization.WinUI.csproj",
+      "..\\..\\src\\Uno.Extensions.Localization\\Uno.Extensions.Localization.csproj",
       "..\\..\\src\\Uno.Extensions.Logging.Serilog\\Uno.Extensions.Logging.Serilog.csproj",
       "..\\..\\src\\Uno.Extensions.Logging\\Uno.Extensions.Logging.WinUI.Skia.csproj",
       "..\\..\\src\\Uno.Extensions.Logging\\Uno.Extensions.Logging.WinUI.Wasm.csproj",

testing/TestHarness/TestHarness.UITest/Constants.cs

@@ -4,7 +4,7 @@ namespace TestHarness.UITest;
 
 public class Constants
 {
-	public readonly static string WebAssemblyDefaultUri = "https://localhost:51571";
+	public readonly static string WebAssemblyDefaultUri = "https://localhost:64052";
 	public readonly static string iOSAppName = "uno.platform.extensions.demo";
 	public readonly static string AndroidAppName = "uno.platform.extensions.demo";
 	public readonly static string iOSDeviceNameOrId = "iPad Pro (12.9-inch) (4th generation)";