Documentation not sufficient for any Xamarin.Forms CustomRenderer Migration in .NET MAUI

[ericbrunner]

The described code in "Reuse custom renderers in .NET MAUI" is only valid for the referenced example, but not for any custom renderer.

I tried to migrate an Entry CustomRenderer and got an InvalidCastException

with the code provided from the docs in the MauiProgram.cs

Workaround: When I add.UseMauiCompatibility() to the MauiAppBuilder and call the .AddCompatibilityRenderer like:

 var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiCompatibility()
            .UseMauiCommunityToolkit()
            .UseMauiApp(serviceProvider => new App(serviceProvider))
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
                fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
            })
            .ConfigureMauiHandlers((mauiHandlerCollection) =>
            {
#if ANDROID
                mauiHandlerCollection.AddCompatibilityRenderer(
                    typeof(MyEntry),
                    typeof(TaskyApp.Droid.CustomRenderer.MyEntryRenderer));
#elif IOS
                mauiHandlerCollection.AddCompatibilityRenderer(
                    typeof(MyEntry),
                    typeof(TaskyApp.iOS.CustomRenderer.MyEntryRenderer));
#endif
            });

it works.

Code example is provided here.

It would be good when the docs get updated to capture any custom renderer reuse.

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Document Details

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• ID: c787fde2-1c9c-62d4-2cdd-93681e0c1ff5
• Version Independent ID: c787fde2-1c9c-62d4-2cdd-93681e0c1ff5
• Content: Reuse custom renderers in .NET MAUI - .NET MAUI
• Content Source: docs/migration/custom-renderers.md
• Product: dotnet-mobile
• Technology: dotnet-maui
• GitHub Login: @davidbritch
• Microsoft Alias: dabritch