Can I use Caliburn to bind to RoutedCommands?

Question

What's the best way to use WPF's built-in RoutedCommands with Caliburn?

For example, in my shell I have an Edit menu with a Copy item in it attached to the standard command found in ApplicationCommands:

<Menu>
    <MenuItem Header="Edit">
        <MenuItem Header="Copy"
                  Command="ApplicationCommands.Copy" />
    </MenuItem>
</Menu>

I want this item to be handled by a TextBox when it has the focus and by my own controls when they have the focus. In my controls I can handle Execute and CanExecute in code behind by creating a CommandBinding:

<UserControl.CommandBindings>
    <CommandBinding Command="ApplicationCommands.Copy"
                    Executed="CopyCommandExecute"
                    CanExecute="CanCopyCommandExecute" />
</UserControl.CommandBindings>

Is there a way, using Caliburn, to handle with methods in my ViewModel instead, or to redirect to another command that I expose from the ViewModel? Or am I going about this the wrong way?

Answer 1

I ended up creating a behaviour that allows the clipboard RoutedCommands to be redirected to other commands.

public class ClipboardBehavior : Behavior<Control>
{
    public static readonly DependencyProperty CopyCommandProperty =
        DependencyProperty.Register("CopyCommand",
                                    typeof (ICommand),
                                    typeof (ClipboardBehavior),
                                    new PropertyMetadata(default(ICommand)));

    public static readonly DependencyProperty CutCommandProperty =
        DependencyProperty.Register("CutCommand",
                                    typeof (ICommand),
                                    typeof (ClipboardBehavior),
                                    new PropertyMetadata(default(ICommand)));

    public static readonly DependencyProperty DeleteCommandProperty =
        DependencyProperty.Register("DeleteCommand",
                                    typeof (ICommand),
                                    typeof (ClipboardBehavior),
                                    new PropertyMetadata(default(ICommand)));

    public static readonly DependencyProperty PasteCommandProperty =
        DependencyProperty.Register("PasteCommand",
                                    typeof (ICommand),
                                    typeof (ClipboardBehavior),
                                    new PropertyMetadata(default(ICommand)));

    public ICommand DeleteCommand
    {
        get { return (ICommand) GetValue(DeleteCommandProperty); }
        set { SetValue(DeleteCommandProperty, value); }
    }

    public ICommand CutCommand
    {
        get { return (ICommand) GetValue(CutCommandProperty); }
        set { SetValue(CutCommandProperty, value); }
    }

    public ICommand CopyCommand
    {
        get { return (ICommand) GetValue(CopyCommandProperty); }
        set { SetValue(CopyCommandProperty, value); }
    }

    public ICommand PasteCommand
    {
        get { return (ICommand) GetValue(PasteCommandProperty); }
        set { SetValue(PasteCommandProperty, value); }
    }

    protected override void OnAttached()
    {
        AddBinding(ApplicationCommands.Delete, () => DeleteCommand);
        AddBinding(ApplicationCommands.Cut, () => CutCommand);
        AddBinding(ApplicationCommands.Copy, () => CopyCommand);
        AddBinding(ApplicationCommands.Paste, () => PasteCommand);
    }

    private void AddBinding(ICommand command, Func<ICommand> executingCommand)
    {
        var binding = new CommandBinding(command,
                                         (sender, e) => Execute(e, executingCommand()),
                                         (sender, e) => CanExecute(e, executingCommand()));

        AssociatedObject.CommandBindings.Add(binding);
    }

    private static void CanExecute(CanExecuteRoutedEventArgs args, ICommand command)
    {
        if (command != null)
        {
            args.CanExecute = command.CanExecute(args.Parameter);
            args.ContinueRouting = false;
        }
    }

    private static void Execute(ExecutedRoutedEventArgs e, ICommand command)
    {
        if (command != null)
            command.Execute(e.Parameter);
    }
}