请问如何实现上下文菜单中,使用Command,调用MyViewModel中定义MyDeleteCommand?下面的调用为何没任何反应呢?在Button中直接使用Command设置是成功的,但在MenuItem中总是不成功,请高人指点,多谢。<Window x:Class="MVVM.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="clr-namespace:MVVM.ViewModels"
        Title="Window1" Height="300" Width="300">
    <Grid>
        <Label  Name="label" Content="Test" Margin="5" MinWidth="60">
            <Label.ContextMenu>
                <ContextMenu Name="contextmenu">
                    <MenuItem Header="删除序列" Command="{Binding MyViewModel.MyDeleteCommand}" CommandParameter="{Binding ElementName=label,Path=Text}"/>
                    
                </ContextMenu>
            </Label.ContextMenu>        </Label>
    </Grid>
</Window>