[BUG] EventToCommandBehavior never invokes commands without CanExecute delegate

[ahoke-cr]

Is there an existing issue for this?

• I have searched the existing issues

Did you read the "Reporting a bug" section on Contributing file?

• I have read the "Reporting a bug" section on Contributing file: https://github.com/CommunityToolkit/Maui/blob/main/CONTRIBUTING.md#reporting-a-bug

Current Behavior

As observed in the source code, only when the command instance explicitly defines a CanExecute value will the behavior execute the command.

Expected Behavior

Commands that don't define CanExecute because they are always valid to execute should also be executed when the behavior proxies a raised event.

Steps To Reproduce

1. Create a Command without a CanExecute delegate
2. Add an EventToCommandBehavior to a view, binding to the command
3. Raise the proxied event

public ICommand TestCommand { get; }

public TestViewModel(...)
{
    TestCommand = new Command(ExecuteMethod);
}

public void ExecuteMethod(object? parameter)
{
    Console.WriteLine("You won't see this");
}

Link to public reproduction project repository

no

Environment

- .NET MAUI CommunityToolkit: 12.2.0
- OS: Win11 x64 23H2 build 22631.5699
- .NET MAUI: 9.0.100

Anything else?

This worked fine in Xamarin.Essentials with XF 5.x so this is a frustrating regression as I upgrade my app on a tight time table.

[dotnet-policy-service]

Hi @@ahoke-cr! We have added the needs reproduction label to this issue, which indicates that we are unable to take further action until you provide a reproduction sample that we can use to reproduce + fix your bug. In accordance with the Reporting a bug section of our Contributing.md that you confirmed reading before you submitted this Issue, we ask that every Issue author provide a link to an open-source repository containing the reproduction sample app. This issue will be closed automatically in 5 days if we do not receive a reproduction sample from you. Please feel free to re-open this Issue once you have provided a reproduction sample.

[bijington]

I suspect something else is going wrong because if no canExecute parameter is passed to a Command then CanExecute will return true: https://github.com/dotnet/maui/blob/b138f16e4beba081c45e45ff54e56245b6fb44e2/src/Controls/src/Core/Command.cs#L109

[ahoke-cr]

I suspect something else is going wrong because if no canExecute parameter is passed to a Command then CanExecute will return true: https://github.com/dotnet/maui/blob/b138f16e4beba081c45e45ff54e56245b6fb44e2/src/Controls/src/Core/Command.cs#L109

I was able to work around this issue by setting the canExecute parameter of the command to a simple lambda _ => true and the issue is suddenly fixed, which is what leads me to believe it's an issue with the CanExecute behavior. As you said, it could be an issue with the command code itself. I'll look into it a little more to see if I can get more details.