用C#语言，怎么监听键盘，请生成一段完整代码

以下是使用 C# 编写的一个实现监听键盘按键的样例程序，该程序以 Windows 窗体应用程序为例。请注意，该代码仅供参考，具体实现可能会因环境、框架版本等因素而有所不同，使用前请仔细阅读其说明文档。

using System;
using System.Windows.Forms;

public class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        HookKeyboard();
    }

    private void InitializeComponent()
    {
        this.SuspendLayout();
        // 
        // Form1
        // 
        this.ClientSize = new System.Drawing.Size(284, 261);
        this.Name = "Form1";
        this.Text = "KeyboardListener";
        this.ResumeLayout(false);
    }

    private void HookKeyboard()
    {
        // 创建键盘钩子
        KeyboardHook hook = new KeyboardHook();
        hook.KeyDown += new KeyboardHook.KeyDownEventHandler(hook_KeyDown);
        hook.KeyUp += new KeyboardHook.KeyUpEventHandler(hook_KeyUp);
    }

    private void hook_KeyDown(object sender, KeyboardHook.KeyDownEventArgs e)
    {
        // 处理键盘按下事件
        Console.WriteLine("KeyDown: " + e.KeyCode.ToString());
    }

    private void hook_KeyUp(object sender, KeyboardHook.KeyUpEventArgs e)
    {
        // 处理键盘松开事件
        Console.WriteLine("KeyUp: " + e.KeyCode.ToString());
    }

    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }
}

public class KeyboardHook
{
    public delegate void KeyDownEventHandler(object sender, KeyDownEventArgs e);
    public delegate void KeyUpEventHandler(object sender, KeyUpEventArgs e);

    public event KeyDownEventHandler KeyDown;
    public event KeyUpEventHandler KeyUp;

    private const int WH_KEYBOARD_LL = 13;
    private const int WM_KEYDOWN = 0x0100;
    private const int WM_KEYUP = 0x0101;

    private LowLevelKeyboardProc keyboardProc;
    private IntPtr hookId = IntPtr.Zero;

    public KeyboardHook()
    {
        keyboardProc = new LowLevelKeyboardProc(HookCallback);
        hookId = SetHook(keyboardProc);
    }

    ~KeyboardHook()
    {
        UnhookWindowsHookEx(hookId);
    }

    private IntPtr SetHook(LowLevelKeyboardProc proc)
    {
        using (Process process = Process.GetCurrentProcess())
        {
            using (ProcessModule module = process.MainModule)
            {
                return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(module.ModuleName), 0);
            }
        }
    }

    private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (nCode >= 0)
        {
            int vkCode = Marshal.ReadInt32(lParam);
            if (wParam == (IntPtr)WM_KEYDOWN && KeyDown != null)
            {
                KeyDown(this, new KeyDownEventArgs(vkCode));
            }
            else if (wParam == (IntPtr)WM_KEYUP && KeyUp != null)
            {
                KeyUp(this, new KeyUpEventArgs(vkCode));
            }
        }
        return CallNextHookEx(hookId, nCode, wParam, lParam);
    }

    private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);

    [StructLayout(LayoutKind.Sequential)]
    private struct KBDLLHOOKSTRUCT
    {
        public int vkCode;
        public int scanCode;
        public int flags;
        public int time;
        public IntPtr dwExtraInfo;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct POINT
    {
        public int x;
        public int y;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct MSG
    {
        public IntPtr hwnd;
        public uint message;
        public IntPtr wParam;
        public IntPtr lParam;
        public uint time;
        public POINT pt;
    }

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

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

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

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

    public class KeyDownEventArgs : EventArgs
    {
        public int KeyCode { get; private set; }

        public KeyDownEventArgs(int keyCode)
        {
            KeyCode = keyCode;
        }
    }

    public class KeyUpEventArgs : EventArgs
    {
        public int KeyCode { get; private set; }

        public KeyUpEventArgs(int keyCode)
        {
            KeyCode = keyCode;
        }
    }
}

在该程序中，我们使用了一个名为 KeyboardHook 的类来实现键盘钩子的注册和处理。该类中定义了 KeyDown 和 KeyUp 两个事件，分别用于处理键盘按下事件和键盘松开事件。在处理事件时，我们可以根据事件参数获取按下的键的信息，例如键码、键名等。

在程序中，我们创建了一个 KeyboardHook 对象，并在构造函数中注册了键盘钩子。在事件处理程序中，我们使用 Console.WriteLine() 方法将按下的键的信息输出到控制台，以便调试和测试。

在使用键盘钩子时，需要注意以下几点：

1. 需要使用 SetWindowsHookEx() 方法注册键盘钩子，该方法会返回一个钩子句柄。在程序结束时，需要使用 UnhookWindowsHookEx() 方法注销键盘钩子，释放资源。

2. 在钩子回调函数中，需要使用 CallNextHookEx() 方法将消息传递给下一个钩子或者系统默认的消息处理函数，否则会导致系统性能下降或者异常。

3. 在使用钩子时，需要注意不要拦截系统级别的按键事件，例如 Ctrl+Alt+Delete、Alt+Tab 等，否则会影响系统的正常运行。