/****************************************************************
* clearMyHook
* Inputs:
* HWND hWnd: Window whose hook is to be cleared
* Result: BOOL
* TRUE if the hook is properly unhooked
* FALSE if you gave the wrong parameter
* Effect:
* Removes the hook that has been set.
****************************************************************/
__declspec(dllexport) BOOL clearMyHook(HWND hWnd)
{
if(hWnd != hWndServer)
return FALSE;
BOOL unhooked = UnhookWindowsHookEx(hook);
if(unhooked)
hWndServer = NULL;
return unhooked;
}
/****************************************************************
* msghook
* Inputs:
* int nCode: Code value
* WPARAM wParam: parameter
* LPARAM lParam: parameter
* Result: LRESULT
*
* Effect:
* If the message is a mouse-move message, posts it back to
* the server window with the mouse coordinates
* Notes:
* This must be a CALLBACK function or it will not work!
****************************************************************/
static LRESULT CALLBACK msghook(int nCode, WPARAM wParam, LPARAM lParam)
{
// If the value of nCode is < 0, just pass it on and return 0
// this is required by the specification of hook handlers
if(nCode < 0)
{ /* pass it on */
CallNextHookEx(hook, nCode,
wParam, lParam);
return 0;
} /* pass it on */
// Read the documentation to discover what WPARAM and LPARAM
// mean. For a WH_MESSAGE hook, LPARAM is specified as being
// a pointer to a MSG structure, so the code below makes that
// structure available
LPMSG msg = (LPMSG)lParam;
// If it is a mouse-move message, either in the client area or
// the non-client area, we want to notify the parent that it has
// occurred. Note the use of PostMessage instead of SendMessage
if(msg->message == WM_MOUSEMOVE ||
msg->message == WM_NCMOUSEMOVE)
PostMessage(hWndServer,
UWM_MOUSEMOVE,
0, 0);
// Pass the message on to the next hook
return CallNextHookEx(hook, nCode,
wParam, lParam);
} // msghook
The server application
在头文件中，将下面的增加到类的protected段：
afx_msg LRESULT OnMyMouseMove(WPARAM,LPARAM);
在application 文件中, 增加以下代码到文件前部。
UINT UWM_MOUSEMOVE = ::RegisterWindowMessage(UWM_MOUSEMOVE_MSG);
在 MESSAGE_MAP, 增加以下代码
//{AFX_MSG comments:
ON_REGISTERED_MESSAGE(UWM_MOUSEMOVE, OnMyMouseMove)
In your application file, add the following function:
LRESULT CMyClass::OnMyMouseMove(WPARAM, LPARAM)
{
// ...do stuff here
return 0;
}
你可以下载这个项目并建立它。 真正的关键是DLL 子工程项目; 其他的都不过是陪衬。有几个其它的技术被用在这个例子里，包括各种各样的图画技术， ClipCursor 和 SetCapture的用法，区域选择、屏幕更新等等。，因此除了展示钩子函数的使用以外，对初级程序员掌握窗口样式设计编程也有一些价值。
