C# wpf鼠标捕获和焦点问题

我在UserControl中有一个文本框。 UserCopControl具有字符串类型的依赖项属性“Text”。 usercontrol的文本属性绑定到TextBox文本属性

public static readonly DependencyProperty TextProperty = DependencyProperty.Register(
        "Text",
        typeof(String),
        typeof(MyTextControl),
        new FrameworkPropertyMetadata(String.Empty, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));

xaml代码

<TextBox
            x:Name="textbox1"
            Text="{Binding ElementName=MyTextControl, Path=Text, UpdateSourceTrigger=LostFocus}"
            ...
</TextBox>

在这种情况下，这对更新非常有用

要捕获此事件，需要在文本更改时设置鼠标捕获，并在单击时释放捕获

private void OnTextBoxTextChanged(object sender, TextChangedEventArgs e)
{
    Mouse.Capture(sender as IInputElement);
}

private void OnPreviewMouseDownOutsideCapturedElement(object sender, MouseButtonEventArgs args)
    {
        var result= VisualTreeHelper.HitTest(this, args.GetPosition(this));
        if (result!= null)
        {
            // clicked inside of usercontrol, can keep capture, no work!
        }
        else
        {
            // outside of usercontrol, now store the text!
            if (_textbox != null)
            {
                _textbox.ReleaseMouseCapture();

                // do other text formatting stuff

                // assign the usercontrols dependency property by the current text
                Text = _textbox.Text;
            }
         }
      }

当实现此机制时，用户单击文本框旁边的某个位置，它发现隧道事件（如任何其他UIElement的PreviewGotKeyboardFocus）不会因为捕获而触发

private void OnPreviewGotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
    {
        // never gets called!
        Debug.WriteLine("   OnPreviewGotKeyboardFocus"); 
    }

如何确保此机制不会阻止其他单击元素的PreviewGotKeyboardFocus事件

private void OnPreviewGotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
    {
        // never gets called!
        Debug.WriteLine("   OnPreviewGotKeyboardFocus"); 
    }