讓WPF的Popup不總置頂的解決方案

使用WPF的Popup的時候會發現有一個問題，它總是會置頂，只要Popup的StayOpen不設置為False，它就一直呆在最頂端，擋住其他的窗口。

解決方案是繼承Popup重新定義控件PopupEx。

 

public class PopupEx : Popup
    {
        public static DependencyProperty TopmostProperty = Window.TopmostProperty.AddOwner(typeof(PopupEx ), new FrameworkPropertyMetadata(false, OnTopmostChanged));
        public bool Topmost
        {
            get { return (bool)GetValue(TopmostProperty); }
            set { SetValue(TopmostProperty, value); }
        }
        private static void OnTopmostChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
        {
            (obj as PopupEx ).UpdateWindow();
        }
        protected override void OnOpened(EventArgs e)
        {
            UpdateWindow();
        }
        private void UpdateWindow()
        {
            var hwnd = ((HwndSource)PresentationSource.FromVisual(this).Handle;
            RECT rect;
            if (GetWindowRect(hwnd, out rect))
            {
                SetWindowPos(hwnd, Topmost ? -1 : -2, rect.Left, rect.Top, (int)this.Width, (int)this.Height, 0);
            }
        }
        #region imports definitions
        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int Left;
            public int Top;
            public int Right;
            public int Bottom;
        }
        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);
        [DllImport("user32", EntryPoint = "SetWindowPos")]
        private static extern int SetWindowPos(IntPtr hWnd, int hwndInsertAfter, int x, int y, int cx, int cy, int wFlags);
        #endregion
    }

 

然后在調用該控件的時候設置該PopupEx的屬性 Topmost=False即可。

 

還有一個Popup的問題，“在父窗口拖動的時候Popup不隨着父窗口移動”的問題的解決方案我會在下一篇隨筆中給出，敬請期待。

轉載時請注明文章來源：http://www.cnblogs.com/Leaco/p/3164394.html