Called before the TextInputUpdate event occurs.
Assembly: System.Windows (in System.Windows.dll)
The method is called before any event handler for the TextInputUpdate event is called. This method allows derived classes to handle the TextInputUpdate event without attaching a delegate. This is the preferred technique for handling the event in a derived class.Notes to Inheritors
When overriding the method in a derived class, be sure to call the base class’s method so that registered delegates receive the event.