数据绑定不适用于用户控件

我正在尝试实现树节点的就地编辑。我离得很近，但没有雪茄。所有绑定似乎都是正确的。应用程序运行良好，没有输出消息，树视图已填充。我能够选择一个节点，按 F2，我可以编辑节点，但一旦我按 Enter 文本就会恢复到之前的状态，就好像我没有进行编辑一样。如果我在应用程序中的其他地方编辑 Name 属性，则更改将反映在 EditableTextBlock 和文本框中。为什么我不能使更改持久化？就好像绑定只以一种方式工作一样。

这是用户控件的 xaml：

<UserControl x:Class="WPFApplication.EditableTextBlock"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WPFApplication"
x:Name="MyUserControl">
<UserControl.Resources>
    <DataTemplate x:Key="EditModeTemplate">
        <TextBox KeyDown="TextBox_KeyDown" Loaded="TextBox_Loaded" LostFocus="TextBox_LostFocus"
                 Text="{Binding Path=Text, ElementName=MyUserControl, Mode=TwoWay}"
                 Margin="0" BorderThickness="1" />
    </DataTemplate>
    <DataTemplate x:Key="DisplayModeTemplate">
        <TextBlock Text="{Binding ElementName=MyUserControl, Path=Text, Mode=TwoWay}"/>
    </DataTemplate>
    <Style TargetType="{x:Type local:EditableTextBlock}">
        <Style.Triggers>
            <Trigger Property="IsInEditMode" Value="True">
                <Setter Property="ContentTemplate" Value="{StaticResource EditModeTemplate}" />
            </Trigger>
            <Trigger Property="IsInEditMode" Value="False">
                <Setter Property="ContentTemplate" Value="{StaticResource DisplayModeTemplate}" />
            </Trigger>
        </Style.Triggers>
    </Style>
</UserControl.Resources>

和背后的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;
namespace WPFApplication
{
    public partial class EditableTextBlock : UserControl
    {
        #region Constructor
        public EditableTextBlock()
        {
            InitializeComponent();
            base.Focusable = true;
            base.FocusVisualStyle = null;
        }
        #endregion Constructor
        #region Member Variables
        // We keep the old text when we go into editmode
        // in case the user aborts with the escape key
        private string oldText;
        #endregion Member Variables
        #region Properties
        public string Text
        {
            get { return (string)GetValue(TextProperty); }
            set { SetValue(TextProperty, value); }
        }
        public static readonly DependencyProperty TextProperty =
            DependencyProperty.Register(
            "Text",
            typeof(string),
            typeof(EditableTextBlock),
            new PropertyMetadata(""));
        public bool IsEditable
        {
            get { return (bool)GetValue(IsEditableProperty); }
            set { SetValue(IsEditableProperty, value); }
        }
        public static readonly DependencyProperty IsEditableProperty =
            DependencyProperty.Register(
            "IsEditable",
            typeof(bool),
            typeof(EditableTextBlock),
            new PropertyMetadata(true));
        public bool IsInEditMode
        {
            get 
            {
                if (IsEditable)
                    return (bool)GetValue(IsInEditModeProperty);
                else
                    return false;
            }
            set
            {
                if (IsEditable)
                {
                    if (value) oldText = Text;
                    SetValue(IsInEditModeProperty, value);
                }
            }
        }
        public static readonly DependencyProperty IsInEditModeProperty =
            DependencyProperty.Register(
            "IsInEditMode",
            typeof(bool),
            typeof(EditableTextBlock),
            new PropertyMetadata(false));
        public string TextFormat
        {
            get { return (string)GetValue(TextFormatProperty); }
            set
            {
                if (value == "") value = "{0}";
                SetValue(TextFormatProperty, value);
            }
        }
        public static readonly DependencyProperty TextFormatProperty =
            DependencyProperty.Register(
            "TextFormat",
            typeof(string),
            typeof(EditableTextBlock),
            new PropertyMetadata("{0}"));
        public string FormattedText
        {
            get { return String.Format(TextFormat, Text); }
        }
        #endregion Properties
        #region Event Handlers
        // Invoked when we enter edit mode.
        void TextBox_Loaded(object sender, RoutedEventArgs e)
        {
            TextBox txt = sender as TextBox;
            // Give the TextBox input focus
            txt.Focus();
            txt.SelectAll();
        }
        // Invoked when we exit edit mode.
        void TextBox_LostFocus(object sender, RoutedEventArgs e)
        {
            this.IsInEditMode = false;
        }
        // Invoked when the user edits the annotation.
        void TextBox_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Enter)
            {
                this.IsInEditMode = false;
                e.Handled = true;
            }
            else if (e.Key == Key.Escape)
            {
                this.IsInEditMode = false;
                Text = oldText;
                e.Handled = true;
            }
        }
        #endregion Event Handlers
    }
}

然后，树视图使用以下数据模板：

<HierarchicalDataTemplate DataType="{x:Type localvm:TreeViewItemViewModel}" ItemsSource="{Binding Children}">
<StackPanel>
    <local:EditableTextBlock Text="{Binding Name}"/>
</StackPanel>

Text="{Binding Path=Text, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:EditableTextBlock}}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"