WPF TreeView 获取SelectedItem

TreeView控件不像ListBox或者ComboBox这些可以绑定SelectedItem
我们可以通过TreeView的SelectedItemChanged事件来进行获取

View中的代码：

<TreeView x:Name="myTreeView" Margin="2" BorderThickness="1" ItemsSource="{Binding TreeViewNodes}">            
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="SelectedItemChanged">
            <i:InvokeCommandAction Command="{Binding Path=TreeNodeSelectedCommand}" CommandParameter="{Binding ElementName=myTreeView, Path=SelectedItem}"/>
        </i:EventTrigger>
    </i:Interaction.Triggers>
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate ItemsSource="{Binding Nodes}">
            <TextBlock Text="{Binding Text}" />
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>    
</TreeView>

ViewModel中的代码：

public ViewModel()
{ 
   
    TreeNodeSelectedCommand = new DelegateCommand<object>(SelectNode);
}

private ObservableCollection<TreeViewNode> m_treeViewNodes = new ObservableCollection<TreeViewNode>();

public ObservableCollection<TreeViewNode> TreeViewNodes
{ 
   
    get => m_treeViewNodes;
    set => SetProperty(ref m_treeViewNodes, value);
}

public DelegateCommand<object> TreeNodeSelectedCommand { 
    get; set; }

private async void SelectNode(object selectedItem)
{ 
   
    // 这样就可以获取到用户所选中的节点了
    var currentNode = selectedItem as TreeViewNode;
}