WPF - How to force a Command to re-evaluate 'CanExecute' via its CommandBindings

Question

I have a Menu where each MenuItem in the hierarchy has its Command property set to a RoutedCommand I\'ve defined. The as

Answer 1

If you have rolled your own class that implements ICommand you can lose a lot of the automatic status updates forcing you to rely on manual refreshing more than should be needed. It can also break InvalidateRequerySuggested(). The problem is that a simple ICommand implementation fails to link the new command to the CommandManager.

The solution is to use the following:

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

    public void RaiseCanExecuteChanged()
    {
        CommandManager.InvalidateRequerySuggested();
    }

This way subscribers attach to CommandManager rather than your class and can properly participate in command status changes.