#604 – Defining a New Routed Event

You can create a new routed event in your own class, typically in a control.  Here, we define a new event named RightDrag in the MyButton class, which derives from Button.

Define a static object of type RoutedEvent.

public static readonly RoutedEvent RightDragEvent;

In the static constructor, register the event and set the RoutedEvent object.

        static MyButton()
        {
            RightDragEvent = EventManager.RegisterRoutedEvent("RightDrag", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(MyButton));
        }

Define a CLR event of type RoutedEventHandler or one of its subtypes.  Call the AddHandler/RemoveHandler methods.

        public event RoutedEventHandler RightDrag
        {
            add { AddHandler(RightDragEvent, value); }
            remove { RemoveHandler(RightDragEvent, value); }
        }

Add a helper method to fire the event.

        protected virtual void OnRightDrag()
        {
            RoutedEventArgs evargs = new RoutedEventArgs(RightDragEvent, this);
            RaiseEvent(evargs);
        }

Finally, fire your event when appropriate.

        void MyButton_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if (e.RightButton == MouseButtonState.Pressed)
                OnRightDrag();
        }

About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

One Response to #604 – Defining a New Routed Event

  1. Pingback: Dew Drop – July 17, 2012 (#1,365) | Alvin Ashcraft's Morning Dew

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