使用 .NET MAUI Community Toolkit MVVM 时按钮变灰

Question

Once clicked, a button turns from blue to grey and will not return to the original blue color.

I create a new .NET MAUI app and install CommunityToolkit.MVVM (V8.0.0). Then create a MainPageViewModel and hook it up to the MainPage View.

In the MainPageViewModel I have two [RelayCommand] methods. One is async and the other is not.

I add two buttons to the MainPage XAML and use the Command attribute to assign each of the 'RelayCommand' handlers to the buttons. The methods just dump to System.Diagnostics.Debug.

When I execute the app on Windows 10 and click the non-async button, I see the diagnostic dump and the button background color remains blue. ie the original color. ie this is the behavior I expect for both buttons.

When I click on the async button, I see the diagnostic dump but the button background color changes from blue to grey. The button is still enabled. If I click again, I see the diagnostic dump again.

How do I get the 'async' button back into the original state.

Snippet from the MainPageViewModel:

    public partial class MainPageViewModel : ObservableObject
    {
        [RelayCommand]
        async Task TestSomethingAsync()
        {
            await Task.Delay(1);
            System.Diagnostics.Debug.WriteLine(nameof(TestSomethingAsync));
        }

        [RelayCommand]
        void TestMore()
        {
            System.Diagnostics.Debug.WriteLine(nameof(TestMore));
        }
    }

Snippet from the MainPage.xaml:

            <Button
                Text="T1 Async"
                Command="{Binding TestSomethingCommand}"
                HorizontalOptions="Center" />
            
            <Button
                Text="T2"
                Command="{Binding TestMoreCommand}"
                HorizontalOptions="Center" />

Answer 1

I am having the same problem. I suspect this is due to an open Maui bug reported on Github: Button IsEnabled property in Windows Platform #7377

When I set up the Button's "IsEnabled" property, programmatically. The expected behavior is working in all platforms. However, the formatting of the button in the Windows Platform gets lost after a couple of changes.

And

The IsEnabled = True works as intended if there was no await call between setting it false and true. But if there is an await call before resetting it to true, the visual element does not reset.