Compatibility: (Revised) Ported Xamarin Forms Effect registration never resolves

Description

While testing a newly ported custom ColorPicker, I ported the control’s touch handling in ColorPickerTouchEffect, which consists of the platform-independent ColorPickerTouchRoutingEffect and the platform-specific ColorPickerTouchEffectXXXX, where XXXX is platform specific (WinUI, Droid, etc) currently being implemented.

During my testing I set breakpoints in each of the Configure… builder calls in MauiProgram and discovered that ConfigureEffects fails to register the PlatformEffect. Both ConfigureFonts and ConfigureMauiHandlers are called as expected. I confirmed that ConfigureEffects IS called because the EffectsFactory and EffectsRegistration are in the builder.

AddCompatibilityEffects, which performs assembly scanning, never resolves the PlatformEffect.

Here is the initialization code:

    public static MauiApp CreateMauiApp()
    { 
        var builder = MauiApp.CreateBuilder();

        builder.UseMauiApp<App>();
        builder.UseSkiaSharp( true );

        builder.ConfigureMauiHandlers( handlers =>
        {
            handlers.TryAddCompatibilityRenderer( typeof( ColorCircle ), typeof( ColorCircle ) );
            handlers.TryAddCompatibilityRenderer( typeof( ColorWheel ), typeof( ColorWheel ) );
            handlers.TryAddCompatibilityRenderer( typeof( ColorTriangle ), typeof( ColorTriangle ) );
            handlers.TryAddCompatibilityRenderer( typeof( AlphaSlider ), typeof( AlphaSlider ) );
            handlers.TryAddCompatibilityRenderer( typeof( LuminositySlider ), typeof( LuminositySlider ) );
            handlers.TryAddCompatibilityRenderer( typeof( RGBSliders ), typeof( RGBSliders ) );
            handlers.TryAddCompatibilityRenderer( typeof( HSLSliders ), typeof( HSLSliders ) );
        } );

        builder.ConfigureFonts( fonts =>
        {
            fonts.AddFont( "OpenSans-Regular.ttf", "OpenSansRegular" );
        } );

        builder.ConfigureEffects( effects =>
        {
            var assemblies = Device.GetAssemblies();
            effects.AddCompatibilityEffects( assemblies );
        } );

        return builder.Build();

Steps to Reproduce

1. Port an XF application that includes an Effect
2. Add builder.ConfigureEffects to MauiProgram to register Effects
3. Launch the application
4. Observe a NRE because the PlatformEffect was not atttached to the RoutingEffect which should occur during Effect resolution.

Version with bug

Preview 12 (current)

Last version that worked well

Unknown/Other

Affected platforms

Android, Windows, I was not able test on other platforms

Affected platform versions

Android 12 and up, Windows SDK 10.0.19041

Did you find any workaround?

Not yet, although I’m still working on it. I filed this because Shane recommended that I do so.

Subsequent debugging revealed that ConfigureEffects is working correctly. Still tracking down why the registration function, AddCompatibilityEffects, doesn’t resolve the Effect.

Relevant log output

None

[IndianaGary]

Thanks for following up. With no movement on the issue I choose to abandon Effects and converted the code to a Behavior which uses a different (and simpler) mechanism. As the Behavior performs the requisite services perfectly, I am abandoning Effects for now.

[samhouts]

@IndianaGary Sorry for the delay getting back to you! I’ll close this for now, but please let us know if you come across further issues. Thank you!!