闲来无事，在WIN2K下用BCB5做了个键盘挂钩小程序，监视全局按键情况。Hook安放和回调函数放在一个单独DLL中，DLL原码如下：
//----------------------------------------------------------------------------------------------------
extern "C" __declspec(dllexport) void __stdcall SetHook(HWND,bool);
LRESULT CALLBACK HookProc(int nCode,WPARAM wParam,LPARAM lParam)
//----------------------------------------------------------------------------------------------------
static HINSTANCE hInstance; // 应用实例句柄
static HWND hWndMain; // MainForm句柄
static HHOOK hKeyHook; // HOOK句柄
static const myMessage=2000; // 自定义消息号
static const SecondPar=1; // 自定义消息第2参数
//----------------------------------------------------------------------------------------------------
int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void* lpReserved)
{ hInstance=hinst; return 1; }
//----------------------------------------------------------------------------------------------------
void __stdcall SetHook(HWND hMainWin,bool nCode)
{
if(nCode) // 安放HOOK
{
hWndMain=hMainWin;
hKeyHook=SetWindowsHookEx(WH_JOURNALRECORD,(HOOKPROC)HookProc,hInstance,0);
}
else // 卸下HOOK
UnhookWindowsHookEx(hKeyHook);
}
//----------------------------------------------------------------------------------------------------
LRESULT CALLBACK HookProc(int nCode,WPARAM wParam,LPARAM lParam)
{
EVENTMSG *keyMSG=(EVENTMSG *)lParam;
if((nCode==HC_ACTION)&&(keyMSG->message==WM_KEYUP))
PostMessage(hWndMain,myMessage,(char)(keyMSG->paramL),SecondPar);
// 向调用窗体发消息myMessage和虚拟键码(char)(keyMSG->paramL)
return((int)CallNextHookEx(hKeyHook,nCode,wParam,lParam));
}
//----------------------------------------------------------------------------------------------------
应用代码如下：（调DLL）
//----------------------------------------------------------------------------------------------------
static HINSTANCE hDLL; // DLL句柄
typedef void __stdcall (*DLLFUN)(HWND,bool);
DLLFUN DLLSetHook;
static const myMessage=2000;
static const SecondPar=1;
//----------------------------------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner):TForm(Owner)
{}
//----------------------------------------------------------------------------------------------------
void __fastcall TForm1::FormCreate(TObject *Sender)
{
hDLL=LoadLibrary((LPCTSTR)"Project1.dll"); // DLL文件名：Project1.dll
if(hDLL==NULL)
{ ShowMessage("DLL: 不能加载！程序退出。"); exit(1); }
DLLSetHook =(DLLFUN)GetProcAddress(hDLL,"SetHook");
if(DLLSetHook==NULL)
{ ShowMessage("DLL: 函数没找到！程序退出。"); FreeLibrary(hDLL); exit(1); }
DLLSetHook(this->Handle,true);
}
//----------------------------------------------------------------------------------------------------
void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
{
DLLSetHook(NULL,false); // 卸下HOOK
FreeLibrary(hDLL); // 卸下DLL
}
//----------------------------------------------------------------------------------------------------
void __fastcall TForm1::ApplicationEvents1Message(tagMSG &Msg,bool &Handled)
{ // BCB5.0 的ApplicationEvents元件
if((Msg.message==myMessage)&&(Msg.lParam==SecondPar))
ShowMessage(" 收到HOOK按键消息！\n\n 【键虚拟码】："+IntToStr(Msg.wParam));
}
//----------------------------------------------------------------------------------------------------
用 WH_JOURNALRECORD 类型HOOK可简单实现.
