我的回答迟到了，但对于那些想要纯 MVVM 解决方案的人来说，这可以通过事件触发器（在用户选择新项目时更新绑定）和数据触发器（更新所选项目）来完成当绑定的值发生变化时）。
为此，主 ViewModel 需要项目、当前选定项目的属性以及当前选定项目更改时将调用的命令属性：
public class MainViewModel : ViewModelBase
{
// the currently selected node, can be changed programmatically
private Node _CurrentNode;
public Node CurrentNode
{
get { return this._CurrentNode; }
set { this._CurrentNode = value; RaisePropertyChanged(() => this.CurrentNode); }
}
// called when the user selects a new node in the tree view
public ICommand SelectedNodeChangedCommand { get { return new RelayCommand<Node>(OnSelectedNodeChanged); } }
private void OnSelectedNodeChanged(Node node)
{
this.CurrentNode = node;
}
// list of items to display in the tree view
private ObservableCollection<Node> _Items;
public ObservableCollection<Node> Items
{
get { return this._Items; }
set { this._Items = value; RaisePropertyChanged(() => this.Items); }
}
}
TreeView 需要一个事件触发器来在选择更改时调用 SelectedNodeChangedCommand，并且需要一个 TreeViewItem 样式的 DataTrigger，以便在代码中以编程方式更改 CurrentNode 的值时选择控件项：
<TreeView x:Name="treeView" ItemsSource="{Binding Items}"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:cmd ="http://www.galasoft.ch/mvvmlight">
<TreeView.Resources>
<conv:EqualityConverter x:Key="EqualityConverter" />
<Style TargetType="TreeViewItem">
<Setter Property="IsExpanded" Value="True" />
<Setter Property="IsSelected" Value="False" />
<Style.Triggers>
<!-- DataTrigger updates TreeViewItem selection when vm code changes CurrentNode -->
<DataTrigger Value="True">
<DataTrigger.Binding>
<MultiBinding Converter="{StaticResource EqualityConverter}">
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type TreeView}}" Path="DataContext.CurrentNode" />
<Binding />
</MultiBinding>
</DataTrigger.Binding>
<Setter Property="IsSelected" Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
<!-- *** HierarchicalDataTemplates go here *** -->
</TreeView.Resources>
<!-- EventTrigger invokes SelectedNodeChangedCommand when selection is changed by user interaction -->
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectedItemChanged">
<cmd:EventToCommand Command="{Binding SelectedNodeChangedCommand}" CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=TreeView}, Path=SelectedItem}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TreeView>
DataTrigger 的工作原理是检测 CurrentNode 的值何时与当前列表项的 Node 匹配。不幸的是，DataTriggers 无法绑定它们的值，因此它必须使用 EqualityConverter 进行测试，而不是进行简单的比较：
public class EqualityConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
return values[0] == values[1];
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}