Avalonia TreeView控件怎么绑定层级数据 Avalonia树状图数据绑定

public class Node : INotifyPropertyChanged
{
    private string _title;
    public string Title
    {
        get => _title;
        set { _title = value; OnPropertyChanged(); }
    }
    public ObservableCollection<Node> SubNodes { get; } = new();
    public event PropertyChangedEventHandler? PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string? name = null) =>
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
}

<TreeView ItemsSource="{Binding RootNodes}">
  <TreeView.ItemTemplate>
    <TreeDataTemplate ItemsSource="{Binding SubNodes}">
      <TextBlock Text="{Binding Title}" />
    </TreeDataTemplate>
  </TreeView.ItemTemplate>
</TreeView>

RootNodes = new ObservableCollection<Node>
{
    new Node { Title = "文档" }
    {
        SubNodes = { new Node { Title = "README.md" }, new Node { Title = "LICENSE" } }
    },
    new Node { Title = "源码" }
    {
        SubNodes = { new Node { Title = "Program.cs" } }
    }
};