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D3DImage.IsFrontBufferAvailable Property

Gets a value that indicates whether a front buffer exists.

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

public bool IsFrontBufferAvailable { get; }

Property Value

Type: System.Boolean
true if a front buffer exists; otherwise, false.

Identifier field

IsFrontBufferAvailableProperty

Metadata properties set to true

None

When IsFrontBufferAvailable is true, back buffer updates are copied forward to the front buffer. If IsFrontBufferAvailable is false, a front buffer does not exist, and nothing is displayed.

Handle the IsFrontBufferAvailableChanged event to be notified when the IsFrontBufferAvailable property changes.

When the IsFrontBufferAvailable property changes from false to true, restart rendering by assigning a valid Direct3D surface in the SetBackBuffer method.

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;
        }
    }
}


.NET Framework

Supported in: 4, 3.5 SP1, 3.0 SP2

.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.

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