The method for handling events which take a ButtonEventArgs object as a parameter.
public delegate void ButtonEventHandler( object sender, ButtonEventArgs e );
Public Delegate Sub ButtonEventHandler( sender As Object, e As ButtonEventArgs )
The event source. This identifies the custom header button which fires the event.
A ButtonEventArgs object that contains data for the event.
When creating a ButtonEventHandler delegate, you identify the method that will handle the corresponding event. To associate an event with your event handler, add a delegate instance to this event. The event handler is called whenever the event occurs unless you remove the delegate. For more information on event handler delegates, see Events and Delegates in MSDN.