Question

Below is the constructor and an event handler in my window.

    public MyWindow() {
        InitializeComponent();

        foreach (RoutedEvent routedEvent in EventManager.GetRoutedEvents())
        {
            EventManager.RegisterClassHandler(typeof(TestUnbuggerWindow), routedEvent, OnRoutedEvent, true);
        }
    }

    public void OnRoutedEvent(Object sender, RoutedEventArgs args)
    {
    }

I’m trying to preview all events, as I’m learning WPF and I think this might expose some of what is going on unseen. Anyway, I get the following build error:

Error   1   The best overloaded method match for 'System.Windows.EventManager.RegisterClassHandler(System.Type, System.Windows.RoutedEvent, System.Delegate, bool)' has some invalid arguments
Error   2   Argument 3: cannot convert from 'method group' to 'System.Delegate'

I got the loop to register for all events from this website.

I believe the problem is caused by the method signature not matching something, but I’m unsure. Could someone shed light on this for me?

Answer 1

you need to use the handler explicity

EventManager.RegisterClassHandler(typeof(TestUnbuggerWindow), 
     routedEvent, new RoutedEventHandler(OnRoutedEvent), true);

It is because you the compiler needs to know what type of handler you want and since the signature takes a Delegate type it cannot infer that you want RoutedEventHandler.