wpf - 如何知道使用mvvm单击哪个treeview项

Question

我有一个WPF MVVM应用程序，该应用程序的TreeView包含所有在XAML页中维护的静态项。我如何在 View 模型中知道单击了哪个MenuItem，以便可以相应地显示相应的页面。

    <TreeView Height="Auto" HorizontalAlignment="Stretch" Margin="0" Name="MyTreeViewMenu" 
                      VerticalAlignment="Stretch" Width="Auto" Opacity="1" 
                     BorderThickness="1" BorderBrush="Black" Grid.Row="2">

        <TreeViewItem Header="Country" Width="Auto" HorizontalAlignment="Stretch" 
                      ></TreeViewItem>

        <TreeViewItem Header="View Details" Width="Auto" HorizontalAlignment="Stretch" IsEnabled="False">
                <TreeViewItem Header="User" />
                <TreeViewItem Header="Group" />
                <TreeViewItem Header="User Group" />
            </TreeViewItem>
    </TreeView>

Answer 1

我想 Selected 事件在您的情况下将与click具有相同的效果。要确定选择了哪一个TreeViewItem，您应该添加事件Trigger:

<TreeView Height="Auto" HorizontalAlignment="Stretch" Margin="0" Name="MyTreeViewMenu" 
                      VerticalAlignment="Stretch" Width="Auto" Opacity="1" 
                     BorderThickness="1" BorderBrush="Black" Grid.Row="2">

        <TreeViewItem Header="Country" Width="Auto" HorizontalAlignment="Stretch"></TreeViewItem>    
        <TreeViewItem Header="View Details" Width="Auto" HorizontalAlignment="Stretch" IsEnabled="False">
                <TreeViewItem Header="User" />
                <TreeViewItem Header="Group" />
                <TreeViewItem Header="User Group" />
            </TreeViewItem>
               <i:Interaction.Triggers>
                  <i:EventTrigger EventName="SelectedItemChanged">
                      <i:InvokeCommandAction 
                         Command="{Binding selectItemCommand}"
                         CommandParameter="{Binding SelectedItem, ElementName=MyTreeViewMenu}"/>
                  </i:EventTrigger>
              </i:Interaction.Triggers>
</TreeView>

结果，您可以使用并确定由传递给 Command的参数选择了哪个项目。
ViewModel应该看起来像这样:

private ICommand _selectItemCommand;
public ICommand selectItemCommand
{
    get
    {
        return _selectItemCommand ?? (_selectItemCommand = new RelayCommand(param => this.LoadPage(param)));
    }
}

private void LoadPage(object selectedMenuItem)
{
      ...
}