When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes.
Assembly: PresentationCore (in PresentationCore.dll)
Changing the reported source of an event programmatically can potentially require updating the type-specific data within the event. For this reason, the method is protected virtual and is intended to be overridden by subclasses of RoutedEventArgs.
This method has no default implementation.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2