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D3DImage.IsFrontBufferAvailable Property

  • Reference

Definition

Namespace:
System.Windows.Interop
Assembly:
PresentationCore.dll

Gets a value that indicates whether a front buffer exists.

public:
 property bool IsFrontBufferAvailable { bool get(); };
public bool IsFrontBufferAvailable { get; }
member this.IsFrontBufferAvailable : bool
Public ReadOnly Property IsFrontBufferAvailable As Boolean

Property Value

Boolean

true if a front buffer exists; otherwise, false.

Examples

The following code example shows how to check the IsFrontBufferAvailable property when rendering the composition target. For more information, see Walkthrough: Hosting Direct3D9 Content in WPF.

void CompositionTarget_Rendering(object sender, EventArgs e)
{
    RenderingEventArgs args = (RenderingEventArgs)e;

    // It's possible for Rendering to call back twice in the same frame 
    // so only render when we haven't already rendered in this frame.
    if (d3dimg.IsFrontBufferAvailable && _lastRender != args.RenderingTime)
    {
        IntPtr pSurface = IntPtr.Zero;
        HRESULT.Check(GetBackBufferNoRef(out pSurface));
        if (pSurface != IntPtr.Zero)
        {
            d3dimg.Lock();
            // Repeatedly calling SetBackBuffer with the same IntPtr is 
            // a no-op. There is no performance penalty.
            d3dimg.SetBackBuffer(D3DResourceType.IDirect3DSurface9, pSurface);
            HRESULT.Check(Render());
            d3dimg.AddDirtyRect(new Int32Rect(0, 0, d3dimg.PixelWidth, d3dimg.PixelHeight));
            d3dimg.Unlock();

            _lastRender = args.RenderingTime;
        }
    }
}

Remarks

Occasionally, the front buffer becomes unavailable. This lack of availability can be caused by screen locking, full-screen exclusive Direct3D applications, user-switching, or other system activities. When this occurs, your WPF application is notified by handling the IsFrontBufferAvailableChanged event. How your application responds to the front buffer becoming unavailable depends on whether WPF is enabled to fall back to software rendering. The SetBackBuffer method has an overload that takes a parameter that specifies whether WPF falls back to software rendering. For more information, see the remarks in the D3DImage class.

Dependency Property Information
Identifier field IsFrontBufferAvailableProperty
Metadata properties set to true None

Applies to

See also