Mine

		internal static void AddHandler (DependencyObject obj, string eventName, UnmanagedEventHandler handler)
		{
			AppDomain domain = AppDomain.CurrentDomain;
			UnmanagedEventHandler wrapper = new UnmanagedEventHandler (delegate (IntPtr target, IntPtr calldata, IntPtr closure) {
				domain.DoCallBack (delegate () { handler (target, calldata, closure); });
			});

			NativeMethods.dependency_object_add_event_handler (obj.native, eventName, wrapper, obj.GCHandle);
		}