How to override methods using Maui Handlers

Question

I have a question, when I used Xamarin there was an option to override control's methods using Renderers.

Now. MAUI has the concept of Handlers. How can I migrate that functionality to MAUI? I see there's code to change the control's appearance (BackgroundColor, etc.) but not much information about overriding methods.

Xamarin example:

public class EditorRendereriOS : EditorRenderer
{
    protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        base.OnElementPropertyChanged(sender, e);
        ...
    }

    // Possible to override methods
    public override bool CanPerform(Selector action, NSObject withSender)
    {
        return base.CanPerform(action, withSender);
    }
}

Thanks in advance.

Answer 1

Hello,

For how to migrate Renderer's functionality to MAUI Handler, please refer to this official documentation.

• Migrate a Xamarin.Forms custom renderer to a .NET MAUI handler.

Update:

After investigation, you can override the methods in the native control with the following steps and associate them into the MAUI control through the handler.

Step 1. Create Native control.

public class MyEntry: UITextField
{
    public override bool CanPerform(Selector action, NSObject withSender)
    {
        Console.WriteLine("test");
        return base.CanPerform(action, withSender);
    }
}

Step 2. Create handler for creating native control.

namespace MauiApp13.Platforms.iOS
{
    public class MyEntryHandler : ViewHandler<Entry, MyEntry>
    {
        public static PropertyMapper<Entry, MyEntryHandler> propertyMapper =
            new PropertyMapper<Entry, MyEntryHandler>();

        public MyEntryHandler() : base(propertyMapper) { }
        protected override MyEntry CreatePlatformView()
        {
            return new MyEntry();
        }
    }
}

Step 3. Register handler.

#if IOS   
                    handler.AddHandler(typeof(Entry), typeof(MauiApp13.Platforms.iOS.MyEntryHandler));
#endif

Best Regards,

Alec Liu.

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