By default this property is set to the associated XamTile's SerializationIdProperty or if that is not specified then the Tile's System.Windows.FrameworkElement.Name.
Note: If this property is still null after the event is processed then no information for this item will be serialized.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2