[UWP] [TreeView - Windows UI库]通过ItemsSource属性添加子项时不起作用。 [英] [UWP] [TreeView - Windows UI Library] Not working when add child through ItemsSource property.

问题描述

   大家好！

    Hi people!

       我需要在我的应用程序中创建一个树导航，然后我去了TreeView控件。但是当一个子项被添加到ObservableCollection时，我没有让它重绘（Binding），这适用于添加/删除根节点的
。我已经尝试了所有文档示例，但没有成功，那会是一个错误吗？
b
$

       I need to create a tree navigation in my application and with that, I went behind a TreeView control. But I'm not getting it to redraw (Binding) when a child is added to the ObservableCollection, this works fine with Add/Remove of root nodes. I've tried all the documentation example, but without success, would that be a bug?

  [XAML]

  [XAML]

<controls:TreeView
               Width="345" 
               MaxHeight="500"
               Margin="0,12,0,0"
               VerticalAlignment="Top"
               HorizontalAlignment="Center"
               ItemsSource="{x:Bind FolderList, Mode=OneWay}"
               ItemTemplate="{StaticResource TreeViewItemDataTemplate}">

 

[代码]

 
[Code]

public ObservableCollection<TreeViewNode> FolderList { get; set; } = new ObservableCollection<TreeViewNode>();

FolderList.First().Children.Add(new TreeViewNode { Content = "Child" });

当我添加孩子时，FolderList不为空。

The FolderList is not empty when I'm adding a child.

关注链接文档：

https://docs.microsoft.com/en-us/windows / uwp / design / controls-and-patterns / tree-view

https://docs.microsoft.com/en-us/windows/uwp/design/controls-and-patterns/tree-view

谢谢，每个人！

推荐答案

问题是TreeViewNode没有自动实现  INO tifyPropertyChanged Interface  。   ObservableCollection auto 实现
接口，但它只影响TreeViewNode对象。但是TreeViewNode中的更改不会由ObservableCollection处理。因此，您可能需要创建一个继承自TreeViewNode类的自定义类，并实现  INotifyPropertyChanged
界面  。那时，如果您将一个子项添加到TreeViewNode，TreeView将会更新。

The problem is that the TreeViewNode does not auto implement the INotifyPropertyChanged Interface . The ObservableCollection auto implements the interface but it only affects the TreeViewNode object. But changes inside the TreeViewNode wont be handled by the ObservableCollection. So you might need to create a customized class inherited from the TreeViewNode class and implement the INotifyPropertyChanged Interface . At that time, if you add a child to the TreeViewNode, the TreeView will be updated.

您可以在此处获得有关数据绑定的更多信息：深度数据绑定。

You could get more information about data binding here:Data binding in depth.

祝你好运，

Roy

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