安装进程内钩子程序（鼠标钩子和键盘钩子）

以最简单的p先生写的hello win98为例，要实现效果是鼠标右键点击客户区之前首先弹出一个消息框（钩子先处理消息，不传递下去），点击空格键之前首先弹出一个消息框，然后再鼠标位置写文本

/*------------------------------------------------------------
HELLOWIN.C -- Displays "Hello, Windows 98!" in client area
(c) Charles Petzold, 1998
------------------------------------------------------------*/

#include <windows.h>

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
 
//回调函数声明，为了尽早见到亲切的主函数，将回调函数的定义写在最后面
LRESULT CALLBACK KeyboardProc(int code, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK MouseProc(int code, WPARAM wParam, LPARAM lParam);

HWND         hwnd ;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
	static TCHAR szAppName[] = TEXT ("HelloWin") ;
	
	MSG          msg ;
	WNDCLASS     wndclass ;
	
	wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
	wndclass.lpfnWndProc   = WndProc ;
	wndclass.cbClsExtra    = 0 ;
	wndclass.cbWndExtra    = 0 ;
	wndclass.hInstance     = hInstance ;
	wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
	wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
	wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
	wndclass.lpszMenuName  = NULL ;
	wndclass.lpszClassName = szAppName ;
	
	if (!RegisterClass (&wndclass))
	{
		MessageBox (NULL, TEXT ("This program requires Windows NT!"), 
			szAppName, MB_ICONERROR) ;
		return 0 ;
	}
	
	hwnd = CreateWindow (szAppName,                  // window class name
						 TEXT ("The Hello Program"), // window caption
						 WS_OVERLAPPEDWINDOW,        // window style
						 CW_USEDEFAULT,              // initial x position
						 CW_USEDEFAULT,              // initial y position
						 CW_USEDEFAULT,              // initial x size
						 CW_USEDEFAULT,              // initial y size
						 NULL,                       // parent window handle
						 NULL,                       // window menu handle
						 hInstance,                  // program instance handle
						 NULL) ;                     // creation parameters
	
	ShowWindow (hwnd, iCmdShow) ;
	UpdateWindow (hwnd) ;
	
	while (GetMessage (&msg, NULL, 0, 0))
	{
		TranslateMessage (&msg) ;
		DispatchMessage (&msg) ;
	}
	return msg.wParam ;
}
HHOOK mouseHook;                  //接收由SetWindowsHookEx返回的旧的钩子
HHOOK keyboardHook;                  //接收由SetWindowsHookEx返回的旧的钩子
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	HDC         hdc ;
	PAINTSTRUCT ps ;
	RECT        rect ;
	POINT point;
	int x, y;
	
	switch (message)
	{
	case WM_CREATE:
		//PlaySound (TEXT ("hellowin.wav"), NULL, SND_FILENAME | SND_ASYNC) ;
		//安装钩子
		mouseHook = SetWindowsHookEx(WH_KEYBOARD,
                                (HOOKPROC)&KeyboardProc,   //回调函数地址
                                NULL, 
                                GetCurrentThreadId());
		keyboardHook = SetWindowsHookEx(WH_MOUSE,
                                (HOOKPROC)&MouseProc,   //回调函数地址
                                NULL, 
                                GetCurrentThreadId());
		return 0 ;

	case WM_KEYDOWN:
		hdc = GetDC(hwnd);

		GetCursorPos(&point);			// 获取鼠标指针位置（屏幕坐标）
		ScreenToClient(hwnd, &point);	// 将鼠标指针位置转换为窗口坐标
		switch(wParam)
		{
		case VK_SPACE:
			TextOut (hdc, point.x, point.y, TEXT("hello left!"), 12);

		}
		ReleaseDC(hwnd, hdc);
		return 0;

	case WM_RBUTTONDOWN:
		hdc = GetDC(hwnd);

		x = LOWORD(lParam);
		y = HIWORD(lParam);
		TextOut (hdc, x, y, TEXT("hello right!"), 12);

		ReleaseDC(hwnd, hdc);
		return 0;

	case WM_PAINT:
		hdc = BeginPaint (hwnd, &ps) ;
		
		GetClientRect (hwnd, &rect) ;
		
		DrawText (hdc, TEXT ("Hello, Windows 98!"), -1, &rect,
			DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;
		
		EndPaint (hwnd, &ps) ;
		return 0 ;
		
	case WM_DESTROY:
		UnhookWindowsHookEx (mouseHook);
		UnhookWindowsHookEx (keyboardHook);
		PostQuitMessage (0) ;		
		return 0 ;
	}
	return DefWindowProc (hwnd, message, wParam, lParam) ;
}

 
//回调函数，用于处理截获的按键消息
LRESULT CALLBACK KeyboardProc(int code, WPARAM wParam, LPARAM lParam)
{
	if(wParam == VK_SPACE)
	{
		MessageBox(hwnd,TEXT("aaa"), TEXT("bbb"), MB_OK);        //输出消息框
		return CallNextHookEx(mouseHook,code,wParam,lParam);  //将消息还给钩子链，不要影响别人
		//return 1;
	}else
	{
		return CallNextHookEx(keyboardHook,code,wParam,lParam);  //将消息还给钩子链，不要影响别人  
	}
}
//回调函数，用于处理截获的按键消息
LRESULT CALLBACK MouseProc(int code, WPARAM wParam, LPARAM lParam)
{
	if(wParam == WM_RBUTTONDOWN)
	{	
		MessageBox(hwnd,TEXT("aaa"), TEXT("bbb"), MB_OK);		
		return 1;
	}else
	{
		return CallNextHookEx(mouseHook,code,wParam,lParam);  //将消息还给钩子链，不要影响别人  
	}
}