Question

我试图让我的应用程序始终在桌面级别上呈现。这意味着我的应用需要忽略LWin + D或RWin + D等关键序列。我试着让它以这种方式工作：

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
    if (prefixSeen)
    {
        if (keyData == Keys.D)
        {
            MessageBox.Show("Got it!");
        }
        prefixSeen = false;
        return true;
    }
    if (keyData == Keys.LWin)
    {
        prefixSeen = true;
        return true;
    }
    return base.ProcessCmdKey(ref msg, keyData);
}

但它只捕获了RWin / LWin按钮，没有D按钮。

我还尝试创建自己的邮件过滤器，但我已经迷失了。所有这些messages和按位：

    public class KeystrokMessageFilter : System.Windows.Forms.IMessageFilter
    {
        public KeystrokMessageFilter() { }

        public bool PreFilterMessage(ref Message m)
        {
            if ((m.Msg == 256 /*0x0100*/))
            {
                switch (((int)m.WParam) | ((int)Control.ModifierKeys))
                {
                    case (int)(Keys.Control | Keys.Alt | Keys.K):
                        MessageBox.Show("You pressed ctrl + alt + k");
                        break;
                    case (int)(Keys.Control | Keys.C): MessageBox.Show("ctrl+c");
                        break;
                    case (int)(Keys.Control | Keys.V): MessageBox.Show("ctrl+v");
                        break;
                    case (int)Keys.Up: MessageBox.Show("You pressed up");
                        break;
                }
            }
            return false;
        }
}

Application.AddMessageFilter(keyStrokeMessageFilter);

那么，如何使我的应用程序捕获/忽略R / LWin + D？

Answer 1

此代码注册一个低级键盘挂钩，并在保持Windows键时侦听D按键。如果检测到这种情况，挂钩就会忽略按键。否则，它会转发按键。

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace KbHook
{
    public static class Program
    {
        const int HC_ACTION = 0;
        const int WH_KEYBOARD_LL = 13;
        const int WM_KEYDOWN = 0x0100;
        static IntPtr HookHandle = IntPtr.Zero;
        static Form1 Form1;

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern IntPtr SetWindowsHookEx(int idHook, KbHook lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern IntPtr GetModuleHandle(string lpModuleName);

        [STAThread]
        static void Main()
        {
            try
            {
                using (var proc = Process.GetCurrentProcess())
                    using (var curModule = proc.MainModule)
                    {
                        var moduleHandle = GetModuleHandle(curModule.ModuleName);
                        HookHandle = SetWindowsHookEx(WH_KEYBOARD_LL, IgnoreWin_D, moduleHandle, 0);
                    }

                Form1 = new Form1();
                Application.Run(Form1);
            }
            finally
            {
                UnhookWindowsHookEx(HookHandle);
            }
        }

        [DllImport("user32.dll")]
        static extern short GetAsyncKeyState(Keys vKey);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

        static IntPtr IgnoreWin_D(int nCode, IntPtr wParam, IntPtr lParam)
        {
            if (nCode == HC_ACTION
                && IsWin_D(wParam, lParam))
                return (IntPtr) 1; //just ignore the key press

            return CallNextHookEx(HookHandle, nCode, wParam, lParam);
        }

        static bool IsWin_D(IntPtr wParam, IntPtr lParam)
        {
            if ((int) wParam != WM_KEYDOWN)
                return false;

            var keyInfo = (KbHookParam) Marshal.PtrToStructure(lParam, typeof (KbHookParam));
            if (keyInfo.VkCode != (int) Keys.D) return false;
            return GetAsyncKeyState(Keys.LWin) < 0
                   || GetAsyncKeyState(Keys.RWin) < 0;
        }

        delegate IntPtr KbHook(int nCode, IntPtr wParam, [In] IntPtr lParam);

        [StructLayout(LayoutKind.Sequential)]
        struct KbHookParam
        {
            public readonly int VkCode;
            public readonly int ScanCode;
            public readonly int Flags;
            public readonly int Time;
            public readonly IntPtr Extra;
        }
    }
}

另见How to hook Win + Tab using LowLevelKeyboardHook

Answer 2

尝试How to detect when a windows form is being minimized?的解决方案，在事件触发并处理之前捕获事件;它应该让你忽略它。

Answer 3

我知道这太老了。但是，嘿，最近我不得不开发一个像小部件一样可以留在桌面上的应用程序（为我公司的年度狂欢倒计时该应用程序）。

即使通过Windows低级键盘钩按WinKey + D或WinKey + M，我也设法使窗口保持在后台（桌面Winform）。我使用了dss539的代码，并对其进行了改进，以使我的winforms应用程序在台式机级别仍然有效。

技巧是在遇到WinKey + D或WinKey + M时将窗体TopMost属性设置为true，然后将其他键设置为false，并将窗口的句柄移交给处理。

下面是示例代码。

在Program.cs中-Main（）

try
{
    using (var proc = Process.GetCurrentProcess())
    using (var curModule = proc.MainModule)
    {
        var moduleHandle = GetModuleHandle(curModule.ModuleName);
        HookHandle = SetWindowsHookEx(WH_KEYBOARD_LL, IgnoreWin_DOrM, moduleHandle, 0);
    }

    frmForm1 = new frmIGS();
    Application.Run(frmForm1);
}
finally
{
    UnhookWindowsHookEx(HookHandle);
}

然后编写键盘钩子方法：

static IntPtr IgnoreWin_DOrM(int nCode, IntPtr wParam, IntPtr lParam)
{
    if (nCode == HC_ACTION
        && (IsWin_D(wParam, lParam) || IsWin_M(wParam, lParam)))
    {
        frmForm1.SetTopMost = true;
    }
    else
    {
        //if (frmForm1.SetTopMost)
        {
            frmForm1.SetTopMost = false;
        }
    }

    return CallNextHookEx(HookHandle, nCode, wParam, lParam);
}

static bool IsWin_D(IntPtr wParam, IntPtr lParam)
{
    if ((int)wParam != WM_KEYDOWN)
        return false;

    var keyInfo = (KbHookParam)Marshal.PtrToStructure(lParam, typeof(KbHookParam));
    if (keyInfo.VkCode != (int)Keys.D) return false;
    return GetAsyncKeyState(Keys.LWin) < 0
            || GetAsyncKeyState(Keys.RWin) < 0;
}

static bool IsWin_M(IntPtr wParam, IntPtr lParam)
{
    if ((int)wParam != WM_KEYDOWN)
        return false;

    var keyInfo = (KbHookParam)Marshal.PtrToStructure(lParam, typeof(KbHookParam));
    if (keyInfo.VkCode != (int)Keys.M) return false;
    return GetAsyncKeyState(Keys.LWin) < 0
            || GetAsyncKeyState(Keys.RWin) < 0;
}

我公开了表单的公共属性，该属性在代码中设置了最高属性！

private bool topMost = false;
public bool SetTopMost
{
    get
    {
        return topMost;
    }
    set
    {

        this.TopMost = topMost = value;
    }
}

中提琴。现在，无论Windows键组合如何，我的代码都可以在后台运行。但是不会停留在其他应用程序之上，从而允许用户执行其正常工作！这就是要求！

在Windows 10中效果很好：）

在Winforms中捕获WinKey + D键序列

3 个答案: