WPF中StaysOpen=False失效时，Popup特殊场景自动关闭方案咨询

针对你遇到的Popup在窗口拖动、外部滚动时不自动关闭的问题，可通过在自定义控件内部添加两个关键事件监听来解决，无需使用者额外编写代码，适配.NET Framework 4.8：

核心思路 #

1. 窗口拖动处理：监听Popup所在顶级窗口的LocationChanged事件，窗口拖动时触发该事件，此时判断鼠标是否在Popup区域外，若在则关闭Popup。
2. 外部滚动处理：订阅应用程序级别的PreviewMouseWheel事件，滚动发生时检查鼠标是否在Popup区域外，若在则关闭Popup，替代遍历ScrollViewer的繁琐方案。

修改后的完整代码 #

[TemplatePart(Name = PopupPartName, Type = typeof(Popup))]
public class PopupButton : ButtonBase
{
    public const string PopupPartName = "PART_Popup";

    private Popup _popup;
    private Window _hostWindow;

    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();
        _popup = GetTemplateChild(PopupPartName) as Popup;
        _popup.Opened += OnPopupOpened;
        _popup.Closed += OnPopupClosed;
    }

    protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
    {
        base.OnMouseLeftButtonDown(e);
        _popup.IsOpen = true;
    }

    protected override void OnLostFocus(RoutedEventArgs e)
    {
        base.OnLostFocus(e);
        _popup.IsOpen = false;
    }

    private void OnPopupOpened(object sender, EventArgs e)
    {
        // 订阅Popup内部的鼠标事件
        _popup.PreviewMouseWheel += OnPopupMouseWheel;
        _popup.PreviewMouseLeftButtonDown += OnPopupMouseLeftButtonDown;

        // 获取顶级窗口并订阅LocationChanged事件（处理窗口拖动）
        _hostWindow = Window.GetWindow(this);
        if (_hostWindow != null)
        {
            _hostWindow.LocationChanged += OnWindowLocationChanged;
        }

        // 订阅应用程序级别的鼠标滚轮事件（处理外部滚动）
        Application.Current.PreviewMouseWheel += OnApplicationMouseWheel;
    }

    private void OnPopupClosed(object sender, EventArgs e)
    {
        // 取消订阅Popup内部事件
        _popup.PreviewMouseWheel -= OnPopupMouseWheel;
        _popup.PreviewMouseLeftButtonDown -= OnPopupMouseLeftButtonDown;

        // 取消订阅窗口事件
        if (_hostWindow != null)
        {
            _hostWindow.LocationChanged -= OnWindowLocationChanged;
            _hostWindow = null;
        }

        // 取消订阅应用程序级事件
        Application.Current.PreviewMouseWheel -= OnApplicationMouseWheel;
    }

    private void OnPopupMouseWheel(object sender, MouseWheelEventArgs e)
    {
        _popup.IsOpen = _popup.IsMouseOver;
    }

    private void OnPopupMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        _popup.IsOpen = _popup.IsMouseOver;
    }

    private void OnWindowLocationChanged(object sender, EventArgs e)
    {
        // 窗口拖动时，检查鼠标是否不在Popup区域内
        if (_popup.IsOpen && !IsMouseOverPopup())
        {
            _popup.IsOpen = false;
        }
    }

    private void OnApplicationMouseWheel(object sender, MouseWheelEventArgs e)
    {
        // 滚动时，检查鼠标是否不在Popup区域内
        if (_popup.IsOpen && !IsMouseOverPopup())
        {
            _popup.IsOpen = false;
        }
    }

    // 判断鼠标是否在Popup的可视化范围内
    private bool IsMouseOverPopup()
    {
        if (_popup.Child == null) return false;

        // 获取Popup在屏幕坐标系中的边界
        var popupScreenPos = _popup.PointToScreen(new Point(0, 0));
        var popupRect = new Rect(
            popupScreenPos,
            new Size(_popup.ActualWidth, _popup.ActualHeight));

        // 获取当前鼠标的屏幕位置
        var mouseScreenPos = Mouse.GetPosition(null);

        return popupRect.Contains(mouseScreenPos);
    }
}

代码说明 #

• 窗口拖动监听：通过Window.GetWindow(this)获取控件所在的顶级窗口，订阅其LocationChanged事件，窗口拖动时触发该事件，调用IsMouseOverPopup判断鼠标位置，若不在Popup内则关闭。
• 全局滚动监听：订阅Application.Current.PreviewMouseWheel事件，任何地方的滚动操作都会触发该事件，同样判断鼠标位置后决定是否关闭Popup。
• 鼠标位置判断：IsMouseOverPopup方法通过屏幕坐标系转换，判断鼠标是否在Popup的可视区域内，避免误判。
• 事件清理：在Popup关闭时取消所有订阅的事件，防止内存泄漏。

验证步骤 #

1. 点击蓝色按钮打开Popup
2. 拖动窗口标题栏，Popup会自动关闭
3. 在Popup外部滚动内容，Popup会自动关闭

内容的提问来源于stack exchange，提问作者Oliver Giesen