Use EventTrigger on a specific key

Question

I would like to invoke a command using EventTrigger when a particular key is touched (for example, the spacebar key)

Currently I have:

Answer 1

I like the idea with a custom trigger but I didn't managed to make it work (some methods were changed or deprecated therefore the showed above definition of the SpaceKeyDownEventTrigger is not compiled now). So, I put here the working version with custom RoutedEvent instead. The SpaceKeyDownEvent is defined in MyControl custom control and is raised from the OnKeyDown method when an unhandled KeyDown attached event reaches MyControl and the key pressed is the spacebar.

public class MyControl : ContentControl
{
    // This constructor is provided automatically if you
    // add a Custom Control (WPF) to your project
    static MyControl()
    {
        DefaultStyleKeyProperty.OverrideMetadata(
            typeof(MyControl),
            new FrameworkPropertyMetadata(typeof(MyControl)));
    }

    // Create a custom routed event by first registering a RoutedEventID
    // This event uses the bubbling routing strategy
    public static readonly RoutedEvent SpaceKeyDownEvent = EventManager.RegisterRoutedEvent(
        "SpaceKeyDown",
        RoutingStrategy.Bubble,
        typeof(RoutedEventHandler),
        typeof(MyControl));

    // Provide CLR accessors for the event
    public event RoutedEventHandler SpaceKeyDown
    {
        add { AddHandler(SpaceKeyDownEvent, value); }
        remove { RemoveHandler(SpaceKeyDownEvent, value); }
    }

    // This method raises the SpaceKeyDown event
    protected virtual void RaiseSpaceKeyDownEvent()
    {
        RoutedEventArgs args = new RoutedEventArgs(SpaceKeyDownEvent);
        RaiseEvent(args);
    }

    // Here KeyDown attached event is customized for the desired key
    protected override void OnKeyDown(KeyEventArgs e)
    {
        base.OnKeyDown(e);

        if (e.Key == Key.Space)
            RaiseSpaceKeyDownEvent();
    }
}

The MyControl could be added to the template of another control, allowing the latter to use EventTrigger with the SpaceKeyDown routed event: