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HwndSource.UsesPerPixelOpacity Property

Gets a value that declares whether the per-pixel opacity of the source window content is respected.

Namespace:  System.Windows.Interop
Assembly:  PresentationCore (in PresentationCore.dll)

public bool UsesPerPixelOpacity { get; }

Property Value

Type: System.Boolean
true if the system uses per-pixel opacity; otherwise, false.

When you enable per-pixel opacity, the system no longer draws the non-client area. This is because the intended purpose of UsesPerPixelOpacity is to show non-rectangular top-level UI that works in interoperation scenarios. Therefore, showing the rectangular non-client area defeats that purpose.

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.