When overridden in a derived class, returns an alternative user interface (UI) parent for this element if no visual parent exists.
Assembly: PresentationCore (in PresentationCore.dll)
The default virtual implementation of this method returns nullptr. FrameworkElement provides a practical implementation.
Alternative parents are used for event routing, in cases where an element creates an alternative parent structure so that its events are routed in a way that diverges from the standard pattern of routing up the visual tree to the standard parent, or downward in the preview routing strategy.
is introduced in the .NET Framework version 3.5. For more information, see .NET Framework Versions and Dependencies.