一、简述

某些应用，我们希望全局自定义热键。按键少了会和别的应用程序冲突，按键多了可定用户操作不变。因此我计划左手用Ctrl+Alt，右手用鼠标右键呼出我自定义的菜单。

我使用键盘和鼠标事件进行简单测试（Ctrl+鼠标右键），发现并不能成功。

RegisterHotKey(hWnd, HOTKEY_ID, (int)Modifiers.Control, (int)Keys.RButton);

因此只好使用“钩子”。

二、添加引用

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Diagnostics;

三、定义变量

private const int WH_MOUSE_LL = 14;
private const int WM_RBUTTONDOWN = 0x0204;
private const int VK_CONTROL = 0x11;
private const int VK_MENU = 0x12;
private HookProc mouseProc;
private IntPtr hookId = IntPtr.Zero;
public event EventHandler HotkeyPressed;

四、编写过程

private IntPtr SetMouseHook(HookProc proc)
{
    using (Process curProcess = Process.GetCurrentProcess())
    using (ProcessModule curModule = curProcess.MainModule)
    {
        return SetWindowsHookEx(WH_MOUSE_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
    }
}
private IntPtr MouseHookCallback(int nCode, IntPtr wParam, IntPtr lParam)
{
    if (nCode >= 0 && wParam == (IntPtr)WM_RBUTTONDOWN)
    {
        int ctrl_keyState = GetAsyncKeyState(VK_CONTROL);
        int alt_keyState = GetAsyncKeyState(VK_MENU);
        // 检查Ctrl键和Alt键是否同时按下
        if ((ctrl_keyState < 0) & (alt_keyState < 0)) 
        {
            HotkeyPressed?.Invoke(this, EventArgs.Empty);
            // 返回非零值以阻止事件传递给其他窗口
            return new IntPtr(1);
        }
    }

    return CallNextHookEx(hookId, nCode, wParam, lParam);
}
private delegate IntPtr HookProc(int code, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hMod, uint dwThreadId);

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

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

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

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern short GetAsyncKeyState(int vKey);

private void HotkeyExample_HotkeyPressed(object sender, EventArgs e)
{
    Console.WriteLine("Ctrl+Alt+鼠标右键被按下");
    // 可以执行其他操作...
    if (this.WindowState == FormWindowState.Minimized)
    {
        POINT M_Point = GetMousePosition();
        this.WindowState = FormWindowState.Normal;
    }
    else
    {
        this.WindowState = FormWindowState.Minimized;
    }
}

五、调用

private void Form1_Load(object sender, EventArgs e)
{
    this.HotkeyPressed += HotkeyExample_HotkeyPressed;

    mouseProc = MouseHookCallback;
    hookId = SetMouseHook(mouseProc);

}
private void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
    UnhookWindowsHookEx(hookId);
}