D3DImage.AddDirtyRect Method (Int32Rect)


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Specifies the area of the back buffer that changed.

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

public void AddDirtyRect(
	Int32Rect dirtyRect


Type: System.Windows.Int32Rect

An Int32Rect that represents the area that changed.

Exception Condition

The bitmap has not been locked by a call to the Lock or TryLock methods.


The back buffer has not been assigned by a call to the SetBackBuffer method.


One or more of the following conditions is true.

dirtyRect.X < 0

dirtyRect.Y < 0

dirtyRect.Width < 0 or dirtyRect.Width > PixelWidth

dirtyRect.Height < 0 or dirtyRect.Height > PixelHeight

Call the AddDirtyRect method to indicate changes your code has made to the back buffer. To be rendered, the changed area on the back buffer must have a corresponding changed area on the D3DImage.

Call the SetBackBuffer and Lock methods before calling the AddDirtyRect method.

Call the Unlock method to copy the changed areas to the front buffer.


After a few calls to the AddDirtyRect method, the changed areas are merged into a single area. This means you must have valid data outside of the changed areas.

The following code example shows how to call the AddDirtyRect method to specify the changed region in the back buffer. For more information, see Walkthrough: Hosting Direct3D9 Content in WPF.

// Repeatedly calling SetBackBuffer with the same IntPtr is 
// a no-op. There is no performance penalty.
d3dimg.SetBackBuffer(D3DResourceType.IDirect3DSurface9, pSurface);
d3dimg.AddDirtyRect(new Int32Rect(0, 0, d3dimg.PixelWidth, d3dimg.PixelHeight));


for access to unmanaged resources. Security action: Demand. Associated enumeration: SecurityPermissionFlag.UnmanagedCode

.NET Framework
Available since 3.0
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