当用户控件失去焦点时更新Viewmodel prop

Question

<UserControl  UIHelper:FocusExtension.IsFocused="{Binding FocusUserControl,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Focusable="True" IsTabStop="True">

在这里，我添加了一个IsFocused道具来保持用户控制的重点

 public static class FocusExtension
    {
        public static bool GetIsFocused(DependencyObject obj)
        {

            return (bool)obj.GetValue(IsFocusedProperty);

        }

        public static void SetIsFocused(DependencyObject obj, bool value)
        {
            obj.SetValue(IsFocusedProperty, value);
        }

        public static readonly DependencyProperty IsFocusedProperty =
            DependencyProperty.RegisterAttached(
                "IsFocused", typeof(bool), typeof(FocusExtension),
                new UIPropertyMetadata(false, OnIsFocusedPropertyChanged));

        private static void OnIsFocusedPropertyChanged(
            DependencyObject d,
            DependencyPropertyChangedEventArgs e)
        {
            var uie = (UIElement)d;
            if ((bool)e.NewValue)
            {
                 uie.Focus();
            }
        }
    }

这是我的FocusExtension类

public bool FocusUserControl
        {
            get { return focusUserControl; }
            set
            {
                focusUserControl = value;
                OnPropertyChanged(new PropertyChangedEventArgs("FocusUserControl"));
            }
        }

这是我的VM道具。已绑定，现在在用户控制中，我有一个按钮。当我单击它时，将新用户控件。那时打开我需要将FocusUserControl更新为false。 不再关注该用户控件。我被困在这里，请提出一些感谢您的帮助。

**

  

更新我添加了类似的内容

**

 private static void OnIsFocusedPropertyChanged(
            DependencyObject d,
            DependencyPropertyChangedEventArgs e)
        {
            uie = (UIElement)d;
            if ((bool)e.NewValue)
            {
                uie.LostKeyboardFocus += LostFocus;
                uie.Focus();
            }

        }
        static void LostFocus(object sender, RoutedEventArgs e)
        {
            uie.LostKeyboardFocus -= LostFocus;
            // Here i need to update `FocusUserControl` to false 
        }

在LostFocus中，我只需要将FocusUserControl更新为false。我该怎么做？真的需要一些帮助。