Windows phone 7 winphn7中的设计部件中未显示映射控件

我正在尝试在WindowsPhone7设计部分中创建添加地图。但我遵循了所有程序。 如果我从工具箱中拖动地图控件，地图将不会显示在设计部分。甚至我给了凭证提供者。这里地图没有显示。我附上了截图，请帮助

这是我的代码：

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,154,0,12">
        <my:Map Height="524" 
                HorizontalAlignment="Left" 
                Name="map1" 
                VerticalAlignment="Top" 
                Width="474" 

                CredentialsProvider="Aj53qt4Oulu0Ez0IVGdNvTVy-swLfo7vCexVzJXJq7hGj1sBYTfSu2t4bPLero2P">
            <!--Enter your bing map key here-->

            <my:Pushpin Name="pin" Background="Transparent" Visibility="Visible">
                <my:Pushpin.Content>
                   <Ellipse Width="20" Height="15" Name="elps" />
                </my:Pushpin.Content>
            </my:Pushpin>
        </my:Map>
            <Button Content="+" Height="72" HorizontalAlignment="Left" Margin="0,52,0,0" Name="button1" VerticalAlignment="Top" Width="72" Background="#00270D0D" FontWeight="Bold" BorderBrush="#FF3CAD0A" Foreground="#FFF62A15" FontSize="28" Click="button1_Click" />
        <Button Content="-" Height="72" HorizontalAlignment="Left" Margin="0,132,0,0" Name="button2" VerticalAlignment="Top" Width="72" Background="#00270D0D" FontWeight="Normal" Foreground="#FFE61919" BorderBrush="#FF1FAA49" FontSize="28" Click="button2_Click" />
    </Grid>
    <Button Content="Find" Grid.Row="1" Height="72" HorizontalAlignment="Left" Margin="0,83,0,0" Name="find" VerticalAlignment="Top" Width="160" Click="find_Click" />
    <Button Content="Change view" Grid.Row="1" Height="72" HorizontalAlignment="Right" Margin="0,83,12,0" Name="view" VerticalAlignment="Top" Width="195" Click="view_Click" />
    <TextBox Grid.Row="1" Height="72" HorizontalAlignment="Left" Margin="156,0,0,0" Name="txtbx" Text="" VerticalAlignment="Top" Width="312" />
    <TextBlock Grid.Row="1" Height="57" HorizontalAlignment="Left" Margin="12,18,0,0" Name="textBlock1" Text="Enter Address" VerticalAlignment="Top" Width="148" TextAlignment="Center" FontSize="22" FontWeight="Bold" Foreground="#FF569E9C" />
</Grid>

  ![this is my screenshot.][1]

  [1]: http://i.stack.imgur.com/0EBGj.jpg

![这是我的截图。][1]
[1]: http://i.stack.imgur.com/0EBGj.jpg

映射控件需要执行WP7设计器中不允许的web请求才能运行。因此，您不会看到任何东西。

您的代码运行良好。添加该控件时，地图将不可见。只需在emulator或设备中运行应用程序，就可以查看地图。但您的模拟器或设备应具有活动的internet连接。