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D3DImage.IsFrontBufferAvailable Property

Updated: July 2008

Gets a value that indicates whether a front buffer exists. This is a dependency property.

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

public bool IsFrontBufferAvailable { get; }
You cannot set this property in XAML.

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;
        }
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

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

.NET Framework

Supported in: 3.5 SP1, 3.0 SP2

Date

History

Reason

July 2008

Added topic for new class.

SP1 feature change.

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