Adds two instances of Duration together.
Assembly: PresentationCore (in PresentationCore.dll)
Return ValueType: System.Windows.Duration
If both instances of Duration have TimeSpan values, this method returns the sum of those two values. If either value is set to Automatic, the method returns Automatic. If either value is set to Forever, the method returns Forever.
If either t1 or t2 has no value, this method returns a null reference (Nothing in Visual Basic).
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.