#599 – A Complete Example of a Routed Event

To help you understand how routed events in WPF work, it’s helpful to look at how they are implemented.  Here is all of the relevant code from the ButtonBase class for the Click event.

    public abstract class ButtonBase : ContentControl, ICommandSource
    {
        // Define/create the routed event object
        public static readonly RoutedEvent ClickEvent = EventManager.RegisterRoutedEvent("Click", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(ButtonBase));

        // CLR event wrapper, adds/removes handlers
        public event RoutedEventHandler Click { add { AddHandler(ClickEvent, value); } remove { RemoveHandler(ClickEvent, value); } }

        // Method used internally to fire the Click event
        protected virtual void OnClick()
        {
            RoutedEventArgs newEvent = new RoutedEventArgs(ButtonBase.ClickEvent, this);
            RaiseEvent(newEvent);
        }
    }

Both the AddHandler and RaiseEvent methods are defined in UIElement.

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 #599 – A Complete Example of a Routed Event

  1. Pingback: Dew Drop – July 11, 2012 (#1,361) | Alvin Ashcraft's Morning Dew

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