本文章從網上復制過來的，復制源找不到了。。。
`
class KeyboardHook
{
public event KeyEventHandler KeyDownEvent;
public event KeyPressEventHandler KeyPressEvent;
public event KeyEventHandler KeyUpEvent;
public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);
static int hKeyboardHook = 0; //聲明鍵盤鈎子處理的初始值
//值在Microsoft SDK的Winuser.h里查詢
public const int WH_KEYBOARD_LL = 13; //線程鍵盤鈎子監聽鼠標消息設為2，全局鍵盤監聽鼠標消息設為13
HookProc KeyboardHookProcedure; //聲明KeyboardHookProcedure作為HookProc類型
//鍵盤結構
[StructLayout(LayoutKind.Sequential)]
public class KeyboardHookStruct
{
public int vkCode; //定一個虛擬鍵碼。該代碼必須有一個價值的范圍1至254
public int scanCode; // 指定的硬件掃描碼的關鍵
public int flags; // 鍵標志
public int time; // 指定的時間戳記的這個訊息
public int dwExtraInfo; // 指定額外信息相關的信息
}
//使用此功能，安裝了一個鈎子
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
//調用此函數卸載鈎子
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern bool UnhookWindowsHookEx(int idHook);
//使用此功能，通過信息鈎子繼續下一個鈎子
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);
// 取得當前線程編號（線程鈎子需要用到）
[DllImport("kernel32.dll")]
static extern int GetCurrentThreadId();
//使用WINDOWS API函數代替獲取當前實例的函數,防止鈎子失效
[DllImport("kernel32.dll")]
public static extern IntPtr GetModuleHandle(string name);
public void Start()
{
// 安裝鍵盤鈎子
if (hKeyboardHook == 0)
{
KeyboardHookProcedure = new HookProc(KeyboardHookProc);
hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardHookProcedure, GetModuleHandle(System.Diagnostics.Process.GetCurrentProcess().MainModule.ModuleName), 0);
//hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardHookProcedure, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);
//************************************
//鍵盤線程鈎子
SetWindowsHookEx(13, KeyboardHookProcedure, IntPtr.Zero, GetCurrentThreadId());//指定要監聽的線程idGetCurrentThreadId(),
//鍵盤全局鈎子,需要引用空間(using System.Reflection;)
//SetWindowsHookEx( 13,MouseHookProcedure,Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),0);
//
//關於SetWindowsHookEx (int idHook, HookProc lpfn, IntPtr hInstance, int threadId)函數將鈎子加入到鈎子鏈表中，說明一下四個參數：
//idHook 鈎子類型，即確定鈎子監聽何種消息，上面的代碼中設為2，即監聽鍵盤消息並且是線程鈎子，如果是全局鈎子監聽鍵盤消息應設為13，
//線程鈎子監聽鼠標消息設為7，全局鈎子監聽鼠標消息設為14。lpfn 鈎子子程的地址指針。如果dwThreadId參數為0 或是一個由別的進程創建的
//線程的標識，lpfn必須指向DLL中的鈎子子程。 除此以外，lpfn可以指向當前進程的一段鈎子子程代碼。鈎子函數的入口地址，當鈎子鈎到任何
//消息后便調用這個函數。hInstance應用程序實例的句柄。標識包含lpfn所指的子程的DLL。如果threadId 標識當前進程創建的一個線程，而且子
//程代碼位於當前進程，hInstance必須為NULL。可以很簡單的設定其為本應用程序的實例句柄。threaded 與安裝的鈎子子程相關聯的線程的標識符
//如果為0，鈎子子程與所有的線程關聯，即為全局鈎子
//************************************
//如果SetWindowsHookEx失敗
if (hKeyboardHook == 0)
{
Stop();
throw new Exception("安裝鍵盤鈎子失敗");
}
}
}
public void Stop()
{
bool retKeyboard = true;
if (hKeyboardHook != 0)
{
retKeyboard = UnhookWindowsHookEx(hKeyboardHook);
hKeyboardHook = 0;
}
if (!(retKeyboard)) throw new Exception("卸載鈎子失敗！");
}
//ToAscii職能的轉換指定的虛擬鍵碼和鍵盤狀態的相應字符或字符
[DllImport("user32")]
public static extern int ToAscii(int uVirtKey, //[in] 指定虛擬關鍵代碼進行翻譯。
int uScanCode, // [in] 指定的硬件掃描碼的關鍵須翻譯成英文。高階位的這個值設定的關鍵，如果是（不壓）
byte[] lpbKeyState, // [in] 指針，以256字節數組，包含當前鍵盤的狀態。每個元素（字節）的數組包含狀態的一個關鍵。如果高階位的字節是一套，關鍵是下跌（按下）。在低比特，如果設置表明，關鍵是對切換。在此功能，只有肘位的CAPS LOCK鍵是相關的。在切換狀態的NUM個鎖和滾動鎖定鍵被忽略。
byte[] lpwTransKey, // [out] 指針的緩沖區收到翻譯字符或字符。
int fuState); // [in] Specifies whether a menu is active. This parameter must be 1 if a menu is active, or 0 otherwise.
//獲取按鍵的狀態
[DllImport("user32")]
public static extern int GetKeyboardState(byte[] pbKeyState);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern short GetKeyState(int vKey);
private const int WM_KEYDOWN = 0x100;//KEYDOWN
private const int WM_KEYUP = 0x101;//KEYUP
private const int WM_SYSKEYDOWN = 0x104;//SYSKEYDOWN
private const int WM_SYSKEYUP = 0x105;//SYSKEYUP
private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
{
// 偵聽鍵盤事件
if ((nCode >= 0) && (KeyDownEvent != null || KeyUpEvent != null || KeyPressEvent != null))
{
KeyboardHookStruct MyKeyboardHookStruct = (KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyboardHookStruct));
// raise KeyDown
if (KeyDownEvent != null && (wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN))
{
Keys keyData = (Keys)MyKeyboardHookStruct.vkCode;
KeyEventArgs e = new KeyEventArgs(keyData);
KeyDownEvent(this, e);
}
//鍵盤按下
if (KeyPressEvent != null && wParam == WM_KEYDOWN)
{
byte[] keyState = new byte[256];
GetKeyboardState(keyState);
byte[] inBuffer = new byte[2];
if (ToAscii(MyKeyboardHookStruct.vkCode, MyKeyboardHookStruct.scanCode, keyState, inBuffer, MyKeyboardHookStruct.flags) == 1)
{
KeyPressEventArgs e = new KeyPressEventArgs((char)inBuffer[0]);
KeyPressEvent(this, e);
}
}
// 鍵盤抬起
if (KeyUpEvent != null && (wParam == WM_KEYUP || wParam == WM_SYSKEYUP))
{
Keys keyData = (Keys)MyKeyboardHookStruct.vkCode;
KeyEventArgs e = new KeyEventArgs(keyData);
KeyUpEvent(this, e);
}
}
//如果返回1，則結束消息，這個消息到此為止，不再傳遞。
//如果返回0或調用CallNextHookEx函數則消息出了這個鈎子繼續往下傳遞，也就是傳給消息真正的接受者
return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
}
~KeyboardHook()
{
Stop();
}
}
`
使用
`
private void hook_KeyDown(object sender, KeyEventArgs e)
{
// 這里寫具體實現
if (e.KeyCode.Equals(Keys.PrintScreen))
{
}
}
/// <summary>
/// 開始監聽
/// </summary>
public void startListen()
{
myKeyEventHandeler = new KeyEventHandler(hook_KeyDown);
k_hook.KeyDownEvent += myKeyEventHandeler;//鈎住鍵按下
k_hook.Start();//安裝鍵盤鈎子
}
/// <summary>
/// 結束監聽
/// </summary>
public void stopListen()
{
if (myKeyEventHandeler != null)
{
k_hook.KeyDownEvent -= myKeyEventHandeler;//取消按鍵事件
myKeyEventHandeler = null;
k_hook.Stop();//關閉鍵盤鈎子
}
}
`