C# XAML MVVM Treeview 控件数据绑定(bind)

Question

我无法显示项目列表。
我究竟做错了什么？

XAML( View ):

<Grid.DataContext>
     <vm:MainViewModel />
</Grid.DataContext>

<Grid.Resources>
     <DataTemplate x:Key="Remedy">
       <TextBlock Text="{Binding Titulo}" />
     </DataTemplate>

     <HierarchicalDataTemplate x:Key="Laboratorio"
                              ItemTemplate="{StaticResource Remedy}"
                              ItemsSource="{Binding Items}">
         <TextBlock Text="{Binding Titulo}" />
     </HierarchicalDataTemplate>
     <HierarchicalDataTemplate x:Key="Root"
                               ItemTemplate="{StaticResource Laboratorio}"
                               ItemsSource="{Binding Items}">
         <TextBlock Text="{Binding Titulo}" />
     </HierarchicalDataTemplate>

</Grid.Resources>

<TreeView x:Name="dirR"
          ItemsSource="{Binding Path=Arbol}"
          ItemTemplate="{StaticResource Root}">
</TreeView>

C#( View 模型):

class MainViewModel:INotifyPropertyChanged
{
   private TreeItem _arbol = new TreeItem("Remedys");
   public TreeItem Arbol
   {
      set 
      { 
         _arbol = value; 
         OnPropertyChanged("Arbol"); 
      }
         get { return _arbol; }
   }

   public MainViewModel()
   {
       //Populate Arbol
       ...
    }
}

C#(模型):

public class TreeItem:INotifyPropertyChanged
{
    private String _titulo;
    private ObservableCollection<TreeItem> _items;
    public String Titulo
    {
        get { return _titulo; }
        set 
        {
            _titulo = value;
            OnPropertyChanged("Titulo");
        } 
    }
    public ObservableCollection<TreeItem> Items
    {
        get { return _items; }
        set 
        {
            _items = value;
            OnPropertyChanged("Items");
        }
    }
    public TreeItem(String __titulo) 
    {
        Titulo = __titulo;
    }

C#(主窗口 v1):

public MainWindow()
{
    InitializeComponent();

}

C# (MainWindow v2) 这个版本工作正常，但我不喜欢它，因为 View 和 Viewmodel 之间存在代码依赖关系

public MainWindow()
{
    InitializeComponent();

    MainViewModel vm = new MainViewModel();
    dirR.Items.Add(vm.Arbol);
}

Answer 1

您只能将值绑定(bind)到 ItemsSource实现IEnumerable .一般来说你必须绑定(bind)一个收藏 至ItemsSource .

更改您的 MainViewModel到

class MainViewModel:INotifyPropertyChanged
{
   private ObservableCollection<TreeItem> _arbol = 
       new ObservableCollection<TreeItem>( 
           new List<TreeItem>
           { 
               new TreeItem("Remedys") 
           } );
   public ObservableCollection<TreeItem> Arbol
   {
      set 
      { 
         _arbol = value; 
         OnPropertyChanged("Arbol"); 
      }
         get { return _arbol; }
   }

   public MainViewModel()
   {
       //Populate Arbol
       ...
    }
}