如何获取在其上执行上下文菜单的控件项的名称

我有几个文本块作为磁贴。我想做的是点按并按住任何textblock然后得到一个contextmenu。我已经这样做了，而且效果很好。当我点击上下文菜单中的菜单项时，我卡住了，我想知道菜单项被点击在哪个文本块上。我怎样才能做到呢?

我已经尝试过这样的事情，但没有运气:

private void MenuItem_Click(object sender, RoutedEventArgs e)
    {
        MenuItem menuItem = (MenuItem)sender;
        var sndr = menuItem.ItemContainerGenerator.ContainerFromItem((sender as ContextMenu).DataContext).ToString();
        // var sndr = menuItem.DataContext.ToString();
        MessageBox.Show("you tapped at " + sndr);
    }

这是上下文菜单和文本块所在的xaml代码:

 <ScrollViewer>
                <toolkit:ContextMenuService.ContextMenu>
                    <toolkit:ContextMenu Name="holdOptions">
                        <toolkit:MenuItem Header="New" Click="MenuItem_Click" />
                        <toolkit:MenuItem Header="Delete" Click="MenuItem_Click"/>
                        <toolkit:MenuItem Header="Clear" Click="MenuItem_Click"/>
                    </toolkit:ContextMenu>
                </toolkit:ContextMenuService.ContextMenu>
                <Grid> 
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="208" />
                    <ColumnDefinition Width="5" />
                    <ColumnDefinition Width="208" />
                    </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="210"/>
                    <RowDefinition Height="5" />
                    <RowDefinition Height="210" />
                    <RowDefinition Height="5" />
                    <RowDefinition Height="210" />
                </Grid.RowDefinitions>
                    <StackPanel Grid.Column="0" Grid.Row="0" Background="{StaticResource PhoneAccentBrush}" Height="205" Width="205">
                        <TextBlock Height="205" Width="205" Name="con1" Text="Tap to add" Tap="con1_Tap" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Center" TextAlignment="Center" FontSize="28" Hold="con1_Hold" />
                    </StackPanel>
                    <StackPanel Grid.Column="2" Grid.Row="0" Background="{StaticResource PhoneAccentBrush}" Height="205" Width="205">
                        <TextBlock Height="205" Width="205" Name="con2" Text="Tap to add" Tap="con2_Tap" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Center" TextAlignment="Center" FontSize="28" Hold="con2_Hold" />
                    </StackPanel>
                    <StackPanel Grid.Column="0" Grid.Row="2" Background="{StaticResource PhoneAccentBrush}" Height="205" Width="205">
                        <TextBlock Height="205" Width="205" Name="con3" Text="Tap to add" Tap="con3_Tap" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Center" TextAlignment="Center" FontSize="28" Hold="con3_Hold" />
                    </StackPanel>
                    <StackPanel Grid.Column="2" Grid.Row="2" Background="{StaticResource PhoneAccentBrush}" Height="205" Width="205">
                        <TextBlock Height="205" Width="205" Name="con4" Text="Tap to add" Tap="con4_Tap" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Center" TextAlignment="Center" FontSize="28" Hold="con4_Hold" />
                    </StackPanel>
            </Grid>
            </ScrollViewer>

    <StackPanel Grid.Column="0" Grid.Row="0" Background="{StaticResource PhoneAccentBrush}" Height="205" Width="205">
        <TextBlock Height="205" Width="205" Name="con1" Text="Tap to add" Tap="con1_Tap" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Center" TextAlignment="Center" FontSize="28" Hold="con1_Hold"/>
          <toolkit:ContextMenuService.ContextMenu>
                <toolkit:ContextMenu Name="holdOptions">
                    <toolkit:MenuItem Header="New" Click="MenuItem_Click" />
                    <toolkit:MenuItem Header="Delete" Click="MenuItem_Click"/>
                    <toolkit:MenuItem Header="Clear" Click="MenuItem_Click"/>
                </toolkit:ContextMenu>
            </toolkit:ContextMenuService.ContextMenu>
        </TextBlock>
    </StackPanel>
    <StackPanel Grid.Column="2" Grid.Row="0" Background="{StaticResource PhoneAccentBrush}" Height="205" Width="205">
        <TextBlock Height="205" Width="205" Name="con2" Text="Tap to add" Tap="con2_Tap" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Center" TextAlignment="Center" FontSize="28" Hold="con2_Hold" >
          <toolkit:ContextMenuService.ContextMenu>
                <toolkit:ContextMenu Name="holdOptions">
                    <toolkit:MenuItem Header="New" Click="MenuItem_Click" />
                    <toolkit:MenuItem Header="Delete" Click="MenuItem_Click"/>
                    <toolkit:MenuItem Header="Clear" Click="MenuItem_Click"/>
                </toolkit:ContextMenu>
            </toolkit:ContextMenuService.ContextMenu>
        </TextBlock>
   </StackPanel>

var menuItem = ((MenuItem)sender);