TreeView.ItemContainerGenerator.ContainerFromItem为非根项目返回null.解决方法？

Question

在下面的示例中,当我选择"String"时,窗口的标题变为"null".但我必须获得"String"的容器.具体来说,我想要做的相当的SelectedItem = null(但物业只为读TreeView,所以我试图去容器设置其IsSelected到false).该怎么办？

<Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Window.Resources>
        <x:Array xmlns="clr-namespace:System;assembly=mscorlib" x:Key="Array" Type="Object">
            <x:ArrayExtension Type="Object">
                <String>String</String>
            </x:ArrayExtension>
        </x:Array>
    </Window.Resources>
    <TreeView ItemsSource="{StaticResource Array}" SelectedItemChanged="Handler">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding}">
                <TextBlock Text="Array"/>
                <HierarchicalDataTemplate.ItemTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding}"/>
                    </DataTemplate>
                </HierarchicalDataTemplate.ItemTemplate>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void Handler(object sender, EventArgs e)
        {
            var treeView = sender as TreeView;
            var container = treeView.ItemContainerGenerator.ContainerFromItem(treeView.SelectedItem);
            Title = container != null ? container.ToString() : "null";
        }
    }
}

Answer 1

问题是每个人TreeViewItem本身就是一个,ItemsControl所以他们每个人都为自己的孩子管理自己的容器.

但是,有一种非常简单的方法可以执行您想要执行的操作:不是注册到SelectedItemChanged事件,而是注册到TreeViewItem.Selected将使用OriginalSource该选项冒泡的事件TreeViewItem.

XAML:

<TreeView ItemsSource="{StaticResource Array}" TreeViewItem.Selected="TreeViewItem_Selected">

代码背后:

private void TreeViewItem_Selected(object sender, RoutedEventArgs e) {
    TreeViewItem container = (TreeViewItem) e.OriginalSource;
    Title = container != null ? container.ToString() : "null";
}