使WPF窗口免于显示桌面(防止隐藏)

Question

我有一个WPF窗口应该是一个"桌面小工具".我的用户正在寻找一种方法来防止它们在点击"显示桌面"时消失.

使窗口始终最顶层,但我的一些用户不希望窗口始终位于顶部.

如果没有每隔x秒运行一次计时器来激活窗口,是否有正确的方法来实现这一目标？

Answer 1

我最终开发了自己的解决方案.我在互联网上搜索了几个星期,试图找到答案,所以我为这个问题感到自豪.

所以我们要做的是使用pinvoke为EVENT_SYSTEM_FOREGROUND窗口事件创建一个钩子.每当前景窗口发生变化时,都会触发此事件.

现在我注意到,当发出"Show Desktop"命令时,WorkerW窗口类变为前景.

请注意,此WorkerW窗口不是桌面,我确认此WorkerW窗口的hwnd不是Desktop hwnd.

所以我们所做的就是当WorkerW窗口成为前景时,我们将"WPF Gadget Window"设置为最顶层!

每当WorkerW窗口之外的窗口成为前景时,我们从"WPF Gadget Window"中删除最顶层的窗口.

如果你想更进一步,你可以取消注释我检查新前景窗口是否也是"PROGMAN"的部分,即桌面窗口.

但是,如果用户在另一台显示器上单击其桌面,这将导致您的窗口成为最顶层.在我的情况下,我不想要这种行为,但我想你们中的一些人可能会这样做.

确认在Windows 10中工作.应该在旧版本的Windows中工作.

using System;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows;

namespace YourNamespace
{
    internal static class NativeMethods
    {
        [DllImport("user32.dll")]
        internal static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, ShowDesktop.WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);

        [DllImport("user32.dll")]
        internal static extern bool UnhookWinEvent(IntPtr hWinEventHook);

        [DllImport("user32.dll")]
        internal static extern int GetClassName(IntPtr hwnd, StringBuilder name, int count);
    }

    public static class ShowDesktop
    {
        private const uint WINEVENT_OUTOFCONTEXT = 0u;
        private const uint EVENT_SYSTEM_FOREGROUND = 3u;

        private const string WORKERW = "WorkerW";
        private const string PROGMAN = "Progman";

        public static void AddHook(Window window)
        {
            if (IsHooked)
            {
                return;
            }

            IsHooked = true;

            _delegate = new WinEventDelegate(WinEventHook);
            _hookIntPtr = NativeMethods.SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, _delegate, 0, 0, WINEVENT_OUTOFCONTEXT);
            _window = window;
        }

        public static void RemoveHook()
        {
            if (!IsHooked)
            {
                return;
            }

            IsHooked = false;

            NativeMethods.UnhookWinEvent(_hookIntPtr.Value);

            _delegate = null;
            _hookIntPtr = null;
            _window = null;
        }

        private static string GetWindowClass(IntPtr hwnd)
        {
            StringBuilder _sb = new StringBuilder(32);
            NativeMethods.GetClassName(hwnd, _sb, _sb.Capacity);
            return _sb.ToString();
        }

        internal delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);

        private static void WinEventHook(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
        {
            if (eventType == EVENT_SYSTEM_FOREGROUND)
            {
                string _class = GetWindowClass(hwnd);

                if (string.Equals(_class, WORKERW, StringComparison.Ordinal) /*|| string.Equals(_class, PROGMAN, StringComparison.Ordinal)*/ )
                {
                    _window.Topmost = true;
                }
                else
                {
                    _window.Topmost = false;
                }
            }
        }

        public static bool IsHooked { get; private set; } = false;

        private static IntPtr? _hookIntPtr { get; set; }

        private static WinEventDelegate _delegate { get; set; }

        private static Window _window { get; set; }
    }
}