简单实现[BCB5]：键盘全局钩子[Hook]，监视多进程键盘操作。

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.

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