Windows Phone图钉重叠

我正在编写一个简单的Windows Phone 7.5本地化应用程序。

我已经改变了默认的图钉模板：

<ControlTemplate TargetType="maps:Pushpin" x:Key="allPushpinsTemplate"> 
     <Grid Height="26" Width="26" Margin="-13,-13,0,0" RenderTransformOrigin="0.5,0.5" > 
      <Grid.RenderTransform> 
       <CompositeTransform Rotation="-45"/> 
      </Grid.RenderTransform> 
      <Rectangle Fill="Black" HorizontalAlignment="Center" Margin="0" Stroke="White" VerticalAlignment="Center" Height="26" Width="26"/> 
      <Ellipse HorizontalAlignment="Center" Height="16" Margin="0" VerticalAlignment="Center" Fill="Red" Width="16"/> 
     </Grid> 
    </ControlTemplate>

当我点击图钉，我处理该事件，并为改变选择销的模板：

 <ControlTemplate TargetType="maps:Pushpin" x:Key="detailedPushpinTemplate"> 
      <Grid x:Name="ContentGrid" Background="Transparent" Margin="-4,0,0,0"> 
       <StackPanel > 
        <Grid Background="Black"> 
         <StackPanel Margin="5,5,0,0"> 
          <TextBlock Text="{Binding Adress}" Foreground="White" /> 
          <StackPanel Orientation="Horizontal"> 
           <TextBlock Text="{Binding ZipCode}" Foreground="White" /> 
           <TextBlock Text="-" Foreground="White" Padding="3,0"/> 
           <TextBlock Text="{Binding City}" Foreground="White" /> 
          </StackPanel> 
          <TextBlock Text="{Binding TelStd}" Foreground="White" /> 
          <TextBlock Text="{Binding Email}" Foreground="White" /> 
          <StackPanel Orientation="Horizontal"> 
           <Button BorderBrush="Transparent" Click="Button_Click" CommandParameter="email" ClickMode="Press"> 
            <Button.Content> 
             <Image Source="/Images/Icons/icon-mail.png" Width="40" Height="40" /> 
            </Button.Content> 
           </Button> 
           <Button BorderBrush="Transparent" Click="Button_Click" CommandParameter="phone" ClickMode="Press"> 
            <Button.Content> 
             <Image Source="/Images/Icons/icon-phone.png" Width="40" Height="40" /> 
            </Button.Content> 
           </Button> 
          </StackPanel> 
         </StackPanel> 
        </Grid> 
        <Polygon Fill="Black" Points="0,0 29,0 0,29" Width="29" Height="29" HorizontalAlignment="Left" /> 
        <Grid Height="26" Width="26" Margin="-13,-13,0,0" RenderTransformOrigin="0.5,0.5" HorizontalAlignment="Left"> 
         <Grid.RenderTransform> 
          <CompositeTransform Rotation="-45"/> 
         </Grid.RenderTransform> 
         <Rectangle Fill="Black" HorizontalAlignment="Center" Margin="0" Stroke="White" VerticalAlignment="Center" Height="26" Width="26" /> 
         <Ellipse HorizontalAlignment="Center" Height="16" Margin="0" VerticalAlignment="Center" Fill="Green" Width="16" /> 
        </Grid> 
       </StackPanel> 
      </Grid> 
    </ControlTemplate>

所以我可以显示一些信息和一些命令。结果完美地工作，并显示一个黑色的矩形与我所有的自定义数据。

但是，其他引脚（默认模板）与矩形重叠并出现在我选定引脚的顶部并隐藏信息。

有没有人有一个想法强制选定的引脚模板始终在其他引脚之上？

信息我的地图的XAML：

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> 
     <Canvas > 
      <maps:Map ZoomBarVisibility="Visible" ZoomLevel="4" Center="46.8821,2.2697" Name="map1" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" Canvas.Top="0" Height="600" Width="460"> 
       <maps:MapItemsControl x:Name="mapControl"/> 
       <maps:MapItemsControl ItemsSource="{Binding Locations}" > 
        <maps:MapItemsControl.ItemTemplate> 
         <DataTemplate> 
          <maps:Pushpin Location="{Binding Location}" Template="{StaticResource allPushpinsTemplate}" MouseLeftButtonDown="Pushpin_MouseLeftButtonDown"/> 
         </DataTemplate> 
        </maps:MapItemsControl.ItemTemplate> 
       </maps:MapItemsControl> 
       <maps:MapLayer Name="imageLayer"/> 
       </maps:Map> 
      <Button Content="some action" Height="70" HorizontalAlignment="Left" Margin="0" Name="button1" VerticalAlignment="Top" Width="170" Canvas.Left="140" /> 
     </Canvas> 

    </Grid>

来源

2012-10-03 Sebastien Roche