支持MVVM Light的CommandParameter

Question

我正在尝试使用MVVM Light让RelayCommand与CommandParameter一起工作。该命令是在我的视图模型中定义的，我希望将所选的ListBox项作为参数传递。命令已绑定，但参数未绑定。这个是可能的吗？

<UserControl x:Class="Nuggets.Metro.Views.EmployeeListView"
         ...
         DataContext="{Binding EmployeeList,Source={StaticResource Locator}}">
   <ListBox x:Name="lstEmployee" ItemsSource="{Binding EmployeeItems}" Style="{StaticResource EmployeeList}" Tag="{Binding EmployeeItems}">
        <ListBox.ContextMenu>
            <ContextMenu DataContext="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
                <MenuItem Header="Edit item" Command="{Binding EditEmployeeCommand}" CommandParameter="{Binding PlacementTarget.SelectedItem,RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}"/>
                <MenuItem Header="Delete item" Command="{Binding DeleteEmployeeCommand}" CommandParameter="{Binding PlacementTarget.SelectedItem,RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}"/>
            </ContextMenu>
        </ListBox.ContextMenu>

Answer 1

这适用于具有MVVM的TreeView或ListView。来自ContextMenu的PlacementTarget是(在这里)列表视图

<ListView.ContextMenu>
  <ContextMenu>
     <MenuItem x:Name="OpenExplorer"Header="ShowFolder"                  
      Command="{Binding ShowExplorer}"
      CommandParameter ="{Binding Path=PlacementTarget.SelectedItem,
            RelativeSource={RelativeSource AncestorType=ContextMenu}}"/>
   </ContextMenu>
</ListView.ContextMenu>