<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>