Window.Current is null in Custom Protocol Activation OnLaunch()

[BertrandDeSaintBezier]

I just created an empty project using the lastest Uno wizard, and have noticed that some things have changed. It appears that the current window is always set to null when launched using custom protocol activation, and this produces a crash when calling the SetWindowIcon function. This used to work perfectly fine on older versions, where this new method simply wasn't being called :

New AppHead class :

using Microsoft.UI.Xaml;
using Uno.Resizetizer;

namespace MyProject
{
    public sealed partial class AppHead : App
    {
        /// <summary>
        /// Initializes the singleton application object. This is the first line of authored code
        /// executed, and as such is the logical equivalent of main() or WinMain().
        /// </summary>
        public AppHead()
        {
            this.InitializeComponent();
        }

        /// <summary>
        /// Invoked when the application is launched normally by the end user.  Other entry points
        /// will be used such as when the application is launched to open a specific file.
        /// </summary>
        /// <param name="args">Details about the launch request and process.</param>
        protected override void OnLaunched(LaunchActivatedEventArgs args)
        {
            base.OnLaunched(args);

            MainWindow.SetWindowIcon();
        }
    }
}

Older AppHead class :

using Microsoft.Extensions.Logging;
using Microsoft.UI.Xaml;
using System;

namespace MyProject
{
    public sealed partial class AppHead : App
    {
        static AppHead() =>
            InitializeLogging();

        /// <summary>
        /// Initializes the singleton application object. This is the first line of authored code
        /// executed, and as such is the logical equivalent of main() or WinMain().
        /// </summary>
        public AppHead()
        {
            this.InitializeComponent();
        }

        /// <summary>
        /// Configures global Uno Platform logging
        /// </summary>
        private static void InitializeLogging()
        {
#if DEBUG
		// Logging is disabled by default for release builds, as it incurs a significant
		// initialization cost from Microsoft.Extensions.Logging setup. If startup performance
		// is a concern for your application, keep this disabled. If you're running on the web or
		// desktop targets, you can use URL or command line parameters to enable it.
		//
		// For more performance documentation: https://platform.uno/docs/articles/Uno-UI-Performance.html

		var factory = LoggerFactory.Create(builder =>
		{
#if __WASM__
			builder.AddProvider(new global::Uno.Extensions.Logging.WebAssembly.WebAssemblyConsoleLoggerProvider());
#elif __IOS__ || __MACCATALYST__
			builder.AddProvider(new global::Uno.Extensions.Logging.OSLogLoggerProvider());
#elif NETFX_CORE
			builder.AddDebug();
#else
			builder.AddConsole();
#endif

			// Exclude logs below this level
			builder.SetMinimumLevel(LogLevel.Information);

			// Default filters for Uno Platform namespaces
			builder.AddFilter("Uno", LogLevel.Warning);
			builder.AddFilter("Windows", LogLevel.Warning);
			builder.AddFilter("Microsoft", LogLevel.Warning);

			// Generic Xaml events
			// builder.AddFilter("Microsoft.UI.Xaml", LogLevel.Debug );
			// builder.AddFilter("Microsoft.UI.Xaml.VisualStateGroup", LogLevel.Debug );
			// builder.AddFilter("Microsoft.UI.Xaml.StateTriggerBase", LogLevel.Debug );
			// builder.AddFilter("Microsoft.UI.Xaml.UIElement", LogLevel.Debug );
			// builder.AddFilter("Microsoft.UI.Xaml.FrameworkElement", LogLevel.Trace );

			// Layouter specific messages
			// builder.AddFilter("Microsoft.UI.Xaml.Controls", LogLevel.Debug );
			// builder.AddFilter("Microsoft.UI.Xaml.Controls.Layouter", LogLevel.Debug );
			// builder.AddFilter("Microsoft.UI.Xaml.Controls.Panel", LogLevel.Debug );

			// builder.AddFilter("Windows.Storage", LogLevel.Debug );

			// Binding related messages
			// builder.AddFilter("Microsoft.UI.Xaml.Data", LogLevel.Debug );
			// builder.AddFilter("Microsoft.UI.Xaml.Data", LogLevel.Debug );

			// Binder memory references tracking
			// builder.AddFilter("Uno.UI.DataBinding.BinderReferenceHolder", LogLevel.Debug );

			// RemoteControl and HotReload related
			// builder.AddFilter("Uno.UI.RemoteControl", LogLevel.Information);

			// Debug JS interop
			// builder.AddFilter("Uno.Foundation.WebAssemblyRuntime", LogLevel.Debug );
		});

		global::Uno.Extensions.LogExtensionPoint.AmbientLoggerFactory = factory;

#if HAS_UNO
		global::Uno.UI.Adapter.Microsoft.Extensions.Logging.LoggingAdapter.Initialize();
#endif
#endif
        }
    }
}

I tried simply commenting out the new method, but as you can imagine that just created other problems :

[jeromelaban]

As this is a WinAppSDK-only behavior, this would be a good question to ask on the Microsoft WinUI repository: https://github.com/microsoft/microsoft-ui-xaml/discussions

[BertrandDeSaintBezier]

Just wanted to check that comment wasn't misleading :

Invoked when the application is launched normally by the end user.

Does this mean that this shouldn't get called when the application is activated via a redirect ?

/// <summary>
/// Invoked when the application is launched normally by the end user.  Other entry points
/// will be used such as when the application is launched to open a specific file.
/// </summary>
/// <param name="args">Details about the launch request and process.</param>
protected override void OnLaunched(LaunchActivatedEventArgs args)
{
    base.OnLaunched(args);
    MainWindow.SetWindowIcon();
}

The answers on the WinAppSDK repo confirm the fact that MainWindow is null, and should be stored inside a static property. This doesn't seem to fix the issue, which appears to be more on the Uno side than the WinAppSDK side

[BertrandDeSaintBezier]

Bumping this as it is still an issue in the latest versions of Uno.

public sealed partial class AppHead : App {
    /// <summary>
    /// Initializes the singleton application object. This is the first line of authored code
    /// executed, and as such is the logical equivalent of main() or WinMain().
    /// </summary>
    public AppHead() {
        this.InitializeComponent();
    }

    public static Window? AppWindowCopy;

    /// <summary>
    /// Invoked when the application is launched normally by the end user.  Other entry points
    /// will be used such as when the application is launched to open a specific file.
    /// </summary>
    /// <param name="args">Details about the launch request and process.</param>
    protected override void OnLaunched(LaunchActivatedEventArgs args) {
        base.OnLaunched(args);

        if (MainWindow != null) {
            AppWindowCopy = MainWindow;
        }
        else if (MainWindow == null) {
            MainWindow = AppWindowCopy;
        }
        MainWindow.SetWindowIcon();
    }
}

When this code is run for the first time (on application startup), MainWindow is not null, so the value is stored in AppWindowCopy. Once the code is run again when the application is launched from protocol activation, both values are null, causing the application to crash when it hits the SetWindowIcon() method.

[jeromelaban]

Thanks for the update. I don't believe this particular code is coming from uno (AppWindowCopy, specifically). Where did you see this code?

[BertrandDeSaintBezier]

This is just a small test I was running. The untouched Uno code only includes the MainWindow.SetWindowIcon() call. This object is always set to null on subsequent activations, however. I was trying to see if storing the variable in a temp copy (AppWindowCopy) would work (it doesn't).

[jeromelaban]

Thanks. For the update. Let's follow in unoplatform/uno.templates#457.

[sasakrsmanovic]

Hey @BertrandDeSaintBezier , given that #457 above was closed, can we mark this one as 'answered'? Thanks