这个问题在这里很好地描述：WPF绑定：使用LostKeyboardFocus而不是LostFocus作为UpdateSourceTrigger 非常有趣看到从微软的家伙知道这个问题几年，但仍然没有固定。
也是一个很大的讨论：保存前的WPF数据绑定

This issue is well described here: WPF Binding: Use LostKeyboardFocus instead of LostFocus as UpdateSourceTrigger Very interesting to see that guys from Microsoft knows about this problem for several years but still not fixed it. Also a big discussing here: WPF Databind Before Saving

这个黑客工程：

    <TabControl SelectionChanged="OnSelectionChanged">

和codebehind：

And codebehind:

    private void OnSelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (Keyboard.FocusedElement is TextBox)
            Keyboard.FocusedElement.RaiseEvent(new RoutedEventArgs(LostFocusEvent));
    }