Symbol的控件模板

<esriSymbols:TextSymbol x:Name="text1" Text="adadfdf"></esriSymbols:TextSymbol>
            <esriSymbols:PictureMarkerSymbol x:Name="DefaultPictureSymbol" OffsetX="35" OffsetY="35"
                 Source="img/i_zoomfull.png" >
                <esriSymbols:PictureMarkerSymbol.ControlTemplate>
                    <ControlTemplate>
                        <Canvas>
                            <TextBlock x:Name="aa" Text="{Binding ElementName=text1, Path=Text}"></TextBlock>
                        </Canvas>
                    </ControlTemplate>
                </esriSymbols:PictureMarkerSymbol.ControlTemplate>
            </esriSymbols:PictureMarkerSymbol>