Assembly: PresentationCore (in PresentationCore.dll)
This method should be implemented by timeline classes that need to provide a custom natural Duration when the Duration property is set to Automatic. If the author cannot determine the natural duration, this method should return Automatic.
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.