Enhancement: Disable button when Command can't execute

[njannink]

When you assign a Command to a Button it would be nice if the Disabled property of the Button would listen to the ICommand.CanExecute(parameter) and the ICommand.CanExecuteChanged event.

[stsrki]

Can you explain better? To tell you the truth I'm not that familiar with IComand.

The Disabled is checked before executing the command

protected async Task ClickHandler()
{
    if ( !Disabled )
    {
        await Clicked.InvokeAsync( null );

        if ( Command?.CanExecute( CommandParameter ) ?? false )
        {
            Command.Execute( CommandParameter );
        }
    }
}

[njannink]

I will have a look if I can make a PR for this.

Mainly what should happen is that when you set the Command or CommandParameter property of a button that you check the CanExecute method of the ICommand and disable the button when this returns false. Also there is an event ICommand.CanExecuteChanged that you should listen to.

This is also how a Wpf button works.

[David-Moreira]

Hello,
How does this affect normal clicking? On the Web, we do have javascript to consider. Does this affect javascript in any way? I might not want the button to disable automatically and still execute bound javascript?

[njannink]

I don't really understand your question, but when you don't assign a command the behavior stays exactly the same as it is now. When you assign a command you will get the expected MVVM behavior as is with Wpf and frameworks like ReactiveUI

[David-Moreira]

Well thanks for the explanation.
It's just me not knowing this feature.

[njannink]

https://www.reactiveui.net/blog/2020/07/article-blazor-compelling-example