检测何时通过键盘将焦点移动到捕获的元素之外

时间:2013-02-21 18:40:46

标签: c# .net wpf

我有这段代码:

Mouse.AddPreviewMouseDownOutsideCapturedElementHandler(this, 
                                                      OnMouseDownOutsideCapture);

当我的WPF弹出窗口外发生鼠标点击时,它会完全捕获(所以我可以关闭它)。

private void OnMouseDownOutsideCapture(object sender, MouseButtonEventArgs e)
{
   if (Mouse.Captured is ComboBox) return;

   if (IsOpen) 
       IsOpen = false;

   ReleaseMouseCapture();
}

但我需要一些方法来了解焦点是否通过键盘移动到弹出窗口之外。更具体地说,通过快捷方式(即Alt + T)。

现在,当用户将焦点移开时,我的弹出窗口不会关闭。有什么想法吗?

2 个答案:

答案 0 :(得分:1)

我就这样做了:

将其添加到构造函数:

EventManager.RegisterClassHandler(typeof(UIElement),
          Keyboard.PreviewGotKeyboardFocusEvent, 
          (KeyboardFocusChangedEventHandler)OnPreviewAnyControlGotKeyboardFocus);

然后添加此事件处理程序:

    /// <summary>
    /// When focus is lost, make sure that we close the popup if needed.
    /// </summary>
    private void OnPreviewAnyControlGotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
    {
        // If we are not open then we are done.  No need to go further
        if (!IsOpen) return;

        // See if our new control is on a popup
        var popupParent = VLTreeWalker.FindParentControl<Popup>((DependencyObject)e.NewFocus);

        // If the new control is not the same popup in our current instance then we want to close.
        if ((popupParent == null) || (this.popup != popupParent))
        {
            popupParent.IsOpen = false;
        }
    }

VLTreeWalker是一个自定义类,它在可视化树中查找与传入的泛型类型匹配,然后(如果找不到匹配项,则会向上走逻辑树。)可悲的是,我不能很容易在这里发布消息来源。

this.popup是您要比较的实例(您想知道它是否应该关闭)。

答案 1 :(得分:0)

您可以添加KeyDown事件并检查是否按下了alt + tab。