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.Navigation.UI/Dispatcher.cs

@@ -33,5 +33,14 @@ public Dispatcher(FrameworkElement element)
 
 	/// <inheritdoc />
 	public async ValueTask<TResult> ExecuteAsync<TResult>(AsyncFunc<TResult> func, CancellationToken cancellation)
-		=> await _dispatcher.ExecuteAsync(func, cancellation);
+	{
+		if (HasThreadAccess)
+		{
+			return await func(cancellation);
+		}
+		return await _dispatcher.ExecuteAsync(func, cancellation);
+	}
+
+	/// <inheritdoc />
+	public bool HasThreadAccess => _dispatcher.HasThreadAccess;
 }

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

@@ -45,11 +45,17 @@ protected Navigator(
 		var regionUpdateId = RouteUpdater?.StartNavigation(Region) ?? Guid.Empty;
 		try
 		{
+
+			if (Dispatcher.HasThreadAccess)
+			{
+				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}");
 				request = request with { Source = this };
-				return await Task.Run(() => NavigateAsync(request));
 			}
 
 

src/Uno.Extensions.Navigation/NavigationRequest.cs

@@ -1,11 +1,9 @@
 namespace Uno.Extensions.Navigation;
 
 #pragma warning disable SA1313 // Parameter names should begin with lower-case letter
-public record NavigationRequest(object Sender, Route Route, CancellationToken? Cancellation = default, Type? Result = null)
+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 INavigator? Source { 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/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)";