上下文菜单MenuItem单击数据上下文？

Question

我有一个对象集合，我已经为其创建了一个ScrollViewer来显示。对于每个对象，数据显示在一个网格中，我在其中添加了一个上下文菜单，以便当用户右击网格时，它们可以更改对象的属性。我不知道如何知道哪个对象已被正确单击。

在下面的代码中，当到达MenuItem "TurnOff“的回调时，我如何知道哪个”TurnOff“是正确单击的？

<ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Hidden" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Grid.ColumnSpan="2" Margin="0,0,0,15">
        <ItemsControl Name="icVoltageMonitorsPanel" ItemsSource="{Binding AppMonitors.VoltageMonitors, Mode=TwoWay}" Grid.ColumnSpan="2" Padding="0" Margin="0"  Width="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ScrollViewer}}, Path=ActualWidth}">
            <ItemsControl.ItemTemplate>
                <DataTemplate DataType="local:VoltageMonitor">
                    <Grid Height="130" Name="grdIndicator" Width="200" MinWidth="200" MinHeight="130">
                        <Grid.ContextMenu>
                            <ContextMenu>
                                <MenuItem Header="Edit Format..." />
                                <MenuItem Header="Turn off" Click="MenuItem_Click" DataContext=""/>
                            </ContextMenu>
                        </Grid.ContextMenu>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="30*" />
                            <RowDefinition Height="25*" />
                            <RowDefinition Height="25*" />
                            <RowDefinition Height="25*" />
                            <RowDefinition Height="25*" />
                        </Grid.RowDefinitions>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="133*" />
                            <ColumnDefinition Width="67*" />
                        </Grid.ColumnDefinitions>

Answer 1

假设您在视图模型中定义了一个ICommand，您可以这样做：

<ItemsControl ...>
      <ItemsControl.ItemTemplate>
          <DataTemplate DataType="local:VoltageMonitor">
              <Grid ..>
                  <Grid.ContextMenu>
                      <ContextMenu>
                          <MenuItem Header="Edit Format..." />
                          <MenuItem Header="Turn off" 
                              CommandParameter="{Binding}"
                              Command="{Binding RelativeSource=
                                   {RelativeSource Mode=FindAncestor, 
                                      AncestorType={x:Type ItemsControl}}, 
                                    Path=DataContext.TurnOffCommand}"/>
                      </ContextMenu>
                  </Grid.ContextMenu>