Assembly: System.Windows (in System.Windows.dll)
This implementation gives focus to the selected item, or to the first item in the list if no item is selected. Do not rely on this method to determine when the control gains focus.
The method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.Notes to Inheritors
When overriding in a derived class, be sure to call the base class’s method so that registered delegates receive the event.