public delegate void VisibilityChangedEventHandler( object sender, VisibilityChangedEventArgs e );
Public Delegate Sub VisibilityChangedEventHandler( sender As Object, e As VisibilityChangedEventArgs )
The event sender. Identifies the dock manager or panel that raised the event.
A VisibilityChangedEventArgs object that contains event data.
When you create a VisibilityChangedEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about delegates, see Events and Delegates in MSDN.