Set CanExecute to be a method of the data context

Question

I could be going about this the wrong way. I am trying to put as little code behind in the view as possible, so I want the CanExecute and Executed events of my command binding to be handled in my viewmodel, which is my data context.

I'm sure I'm missing something really simple, but I can't think how to do it.

The XAML for the command binding:

<UserControl.CommandBindings>
    <CommandBinding Command="DataControls:ParameterCollectionViewModel.UpdateCollection"
                    CanExecute="???"
                    Executed="???"
                    />
</UserControl.CommandBindings>

DataControls:ParameterCollectionViewModel.UpdateCollection is a static RoutedCommand, but the data context is of type ParameterCollectionViewModel (not that it matters).

How do I get the event handlers in my data context to be the event handlers in the command binding?

score 2 · Accepted Answer · answered Mar 09 '11 at 12:23

2

You would probably be much happier if you used a DelegateCommand or something similar (an implementation also exists in the Microsoft Prism sources).

answered Mar 09 '11 at 12:23

Jon

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Thanks for the info. This is the method I've gone for. – Matt Ellen Mar 09 '11 at 13:57

score 0 · Answer 2 · answered Mar 09 '11 at 12:39

Simply said, you need to add the command to your datacontext. If the datacontext is a DependencyObject, you can simply add a new command to the Commands property.

If the datacontext is not a dependency property, I better hope it's a view model. In that case, you can use RelayCommand or DelegateCommand (actually, they are both the same).

I am one of the developers of Catel, an open-source MVVM framework, which also supports commands. You can find more information about Catel commands.

Set CanExecute to be a method of the data context

2 Answers2