C#_键盘钩子

一、class

 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; //声明键盘钩子处理的初始值//值在Microsoft SDK的Winuser.h里查询public const int WH_KEYBOARD_LL = 13;   //线程键盘钩子监听鼠标消息设为2，全局键盘监听鼠标消息设为13HookProc KeyboardHookProcedure; //声明KeyboardHookProcedure作为HookProc类型//键盘结构[StructLayout(LayoutKind.Sequential)]public class KeyboardHookStruct{public int vkCode;  //定一个虚拟键码。该代码必须有一个价值的范围1至254public int scanCode; // 指定的硬件扫描码的关键public int flags;  // 键标志public int time; // 指定的时间戳记的这个讯息public int dwExtraInfo; // 指定额外信息相关的信息}//使用此功能，安装了一个钩子[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);//调用此函数卸载钩子[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]public static extern bool UnhookWindowsHookEx(int idHook);//使用此功能，通过信息钩子继续下一个钩子[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);// 取得当前线程编号（线程钩子需要用到）[DllImport("kernel32.dll")]static extern int GetCurrentThreadId();//使用WINDOWS API函数代替获取当前实例的函数,防止钩子失效[DllImport("kernel32.dll")]public static extern IntPtr GetModuleHandle(string name);public void Start(){// 安装键盘钩子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);//************************************//键盘线程钩子//SetWindowsHookEx( 2,KeyboardHookProcedure, IntPtr.Zero, GetCurrentThreadId());//指定要监听的线程idGetCurrentThreadId(),//键盘全局钩子,需要引用空间(using System.Reflection;)//SetWindowsHookEx( 13,MouseHookProcedure,Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),0);////关于SetWindowsHookEx (int idHook, HookProc lpfn, IntPtr hInstance, int threadId)函数将钩子加入到钩子链表中，说明一下四个参数：//idHook 钩子类型，即确定钩子监听何种消息，上面的代码中设为2，即监听键盘消息并且是线程钩子，如果是全局钩子监听键盘消息应设为13，//线程钩子监听鼠标消息设为7，全局钩子监听鼠标消息设为14。lpfn 钩子子程的地址指针。如果dwThreadId参数为0 或是一个由别的进程创建的//线程的标识，lpfn必须指向DLL中的钩子子程。 除此以外，lpfn可以指向当前进程的一段钩子子程代码。钩子函数的入口地址，当钩子钩到任何//消息后便调用这个函数。hInstance应用程序实例的句柄。标识包含lpfn所指的子程的DLL。如果threadId 标识当前进程创建的一个线程，而且子//程代码位于当前进程，hInstance必须为NULL。可以很简单的设定其为本应用程序的实例句柄。threaded 与安装的钩子子程相关联的线程的标识符//如果为0，钩子子程与所有的线程关联，即为全局钩子//************************************//如果SetWindowsHookEx失败if (hKeyboardHook == 0){Stop();throw new Exception("安装键盘钩子失败");}}}public void Stop(){bool retKeyboard = true;if (hKeyboardHook != 0){retKeyboard = UnhookWindowsHookEx(hKeyboardHook);hKeyboardHook = 0;}if (!(retKeyboard)) throw new Exception("卸载钩子失败！");}//ToAscii职能的转换指定的虚拟键码和键盘状态的相应字符或字符[DllImport("user32")]public static extern int ToAscii(int uVirtKey, //[in] 指定虚拟关键代码进行翻译。int uScanCode, // [in] 指定的硬件扫描码的关键须翻译成英文。高阶位的这个值设定的关键，如果是（不压）byte[] lpbKeyState, // [in] 指针，以256字节数组，包含当前键盘的状态。每个元素（字节）的数组包含状态的一个关键。如果高阶位的字节是一套，关键是下跌（按下）。在低比特，如果设置表明，关键是对切换。在此功能，只有肘位的CAPS LOCK键是相关的。在切换状态的NUM个锁和滚动锁定键被忽略。byte[] lpwTransKey, // [out] 指针的缓冲区收到翻译字符或字符。int fuState); // [in] Specifies whether a menu is active. This parameter must be 1 if a menu is active, or 0 otherwise.//获取按键的状态[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;//KEYDOWNprivate const int WM_KEYUP = 0x101;//KEYUPprivate const int WM_SYSKEYDOWN = 0x104;//SYSKEYDOWNprivate const int WM_SYSKEYUP = 0x105;//SYSKEYUPprivate int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam){// 侦听键盘事件if ((nCode >= 0) && (KeyDownEvent != null || KeyUpEvent != null || KeyPressEvent != null)){KeyboardHookStruct MyKeyboardHookStruct = (KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyboardHookStruct));// raise KeyDownif (KeyDownEvent != null && (wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN)){Keys keyData = (Keys)MyKeyboardHookStruct.vkCode;KeyEventArgs e = new KeyEventArgs(keyData);KeyDownEvent(this, e);}//键盘按下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);}}// 键盘抬起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，则结束消息，这个消息到此为止，不再传递。//如果返回0或调用CallNextHookEx函数则消息出了这个钩子继续往下传递，也就是传给消息真正的接受者return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);}~KeyboardHook(){Stop();}}

二、调用

        private void Form1_Load(object sender, EventArgs e){KeyboardHook keyboardHook = new KeyboardHook();keyboardHook.KeyDownEvent += new KeyEventHandler(hook_KeyDown);//钩住键按下keyboardHook.Start();//安装键盘钩子}private void hook_KeyDown(object sender, KeyEventArgs e){//判断按下的键（Ctrl + D）停止执行if (e.KeyValue == (int)System.Windows.Forms.Keys.D && (int)Control.ModifierKeys == (int)System.Windows.Forms.Keys.Control){Application.Exit();}}