[Enhancement] RadioButton.ButtonSource: custom images for RadioButton

[jfversluis]

Summary

Initially the RadioButton had an API to use a custom image for the bullet. Upon further inspection this was only implemented on Android and missing on iOS, UWP and MacOS. To not block the next release and still have RadioButton, the API was removed for now and this issue is here to track the progress on (re)implementing the ButtonSource API.

Related:

• Original PR RadioButton Implementation #8910
• Bug [Bug] RadioButton.ButtonSource is only implemented on Android #9948
• Removal PR Remove RadioButton.ButtonSource API #9967

API Changes

Add/reenable this API in the RadioButton:

• public static readonly BindableProperty ButtonSourceProperty
• public ImageSource ButtonSource { get; set; }

Intended Use Case

Being able to use a custom image for the RadioButton bullet. Through the VisualStateManager people are able to supply images for both the checked and unchecked state.

[rookiejava]

Hey @jfversluis, do RadioButton need to inherit Button?
If you need Font, Text, and Border related properties, we'd better implement IFontElement, IBorderElement, IBorderElement instead.

[jfversluis]

Technically it doesn't have to. This was taken over from a community PR and implemented like this. Possibly before the mentioned interfaces were available back then.

I think the way CheckBox was implemented would also make more sense here.

[jfversluis]

Thanks for this suggestion! As Xamarin.Forms is now in maintenance mode, this will not happen anymore for Xamarin.Forms. We're only adding bugfixes and stability fixes.

If this is still important to you, make sure to check the .NET MAUI repo and see if it's already on the roadmap. If not, feel free to open a discussion to discuss a change first or open an issue with a detailed feature request. Thanks!