在Viewport2DVisual3D中使用WebBrowser控件 的问题

Question

            <Viewport2DVisual3D x:Name="Side1">

                <!-- Rotation definieren -->

                <Viewport2DVisual3D.Transform>
                    <Transform3DGroup>
                        <RotateTransform3D>

                            <!--<RotateTransform3D.Rotation>

                                <AxisAngleRotation3D x:Name="rot"  Angle="0" Axis="0,0,0" />

                            </RotateTransform3D.Rotation>-->

                        </RotateTransform3D>
                        <TranslateTransform3D OffsetX="0" OffsetY="0" OffsetZ="0" x:Name="Tr1"/>
                        <!--<ScaleTransform3D CenterX="0" CenterY="0"
                                   CenterZ="0" ScaleX="1.5" ScaleY="1" />-->
                    </Transform3DGroup>
                </Viewport2DVisual3D.Transform>



                <!-- Geometry und Material für das Viewport2DVisual3D -->

                <Viewport2DVisual3D.Geometry>

                    <MeshGeometry3D Positions="-1,1,1 -1,-1,1 1,-1,1 1,1,1"

       TextureCoordinates="0,0 0,1 1,1 1,0" 

       TriangleIndices="0 1 2 0 2 3" />

                </Viewport2DVisual3D.Geometry>

                <Viewport2DVisual3D.Material>

                    <DiffuseMaterial Viewport2DVisual3D.IsVisualHostMaterial="True" Brush="Transparent"/>

                </Viewport2DVisual3D.Material>
                <Viewport2DVisual3D.Visual>
                        <Grid Width="300" Height="300">
                         <WebBrowser  Name="Wb1" />                        
                        </Grid>
                </Viewport2DVisual3D.Visual>
            </Viewport2DVisual3D>

用上面的代码把WebBrowser显示在3D表面没有任何效果