'Declaration Public ReadOnly Property Alpha As Nullable(Of Double)
public Nullable<double> Alpha {get;}
Use this property to control the transparency of the associated color.
For example, to make the associated color 50% transparent, assign a value of .5 to this property.
Assigning a value of null to this property implies that the associated color has no specific alpha channel setting, i.e., the associated color is fully opaque.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, 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