如何在C#中设置和使用全局钩子

在C#中设置和使用全局钩子通常涉及到使用Windows API函数，这需要P/Invoke

1. 首先，添加以下命名空间引用：

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

2. 定义一些必要的常量和委托：

public class GlobalHook
{
    public const int WH_KEYBOARD_LL = 13;
    public const int WM_KEYDOWN = 0x0100;
    public const int WM_KEYUP = 0x0101;

    public delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
}

3. 导入所需的Windows API函数：

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(int idHook, GlobalHook.LowLevelKeyboardProc 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);

4. 创建钩子并处理键盘事件：

public class GlobalHook
{
    // ... 其他代码 ...

    private IntPtr _hookID = IntPtr.Zero;
    private GlobalHook.LowLevelKeyboardProc _proc;

    public void SetHook()
    {
        using (Process curProcess = Process.GetCurrentProcess())
        using (ProcessModule curModule = curProcess.MainModule)
        {
            _proc = HookCallback;
            _hookID = SetWindowsHookEx(WH_KEYBOARD_LL, _proc, GetModuleHandle(curModule.ModuleName), 0);
        }
    }

    public void UnsetHook()
    {
        UnhookWindowsHookEx(_hookID);
    }

    private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (nCode >= 0 && (wParam == (IntPtr)WM_KEYDOWN || wParam == (IntPtr)WM_KEYUP))
        {
            int vkCode = Marshal.ReadInt32(lParam);
            Console.WriteLine((Keys)vkCode);
        }

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

5. 最后，在你的程序中使用这个全局钩子：

public static void Main()
{
    GlobalHook globalHook = new GlobalHook();
    globalHook.SetHook();

    Application.Run(); // 保持程序运行，直到用户关闭它

    globalHook.UnsetHook();
}

请注意，全局钩子可能会影响系统性能，因此请谨慎使用。此外，这种方法可能不适用于所有场景，特别是在某些安全策略严格的环境中。在实际应用中，请确保遵循最佳实践和适当的安全措施。