第八章 计时器（BEEPER2）

 /*-------------------------------------
 BEEPER2.C -- Timer Demo Program No.1
              (c) Charles Petzold, 1998
 -------------------------------------*/

 #include <Windows.h>

 #define ID_TIMER 1

 LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 VOID CALLBACK TimerPorc(HWND, UINT, UINT, DWORD);

 int WINAPI WinMain( __in HINSTANCE hInstance
                     , __in_opt HINSTANCE hPrevInstance
                     , __in LPSTR lpCmdLine
                     , __in int nShowCmd )
 {
     static TCHAR szAppName[] = TEXT("Bepper2");
     HWND hwnd;
     MSG msg;
     WNDCLASS wndclass;

     wndclass.style = CS_HREDRAW | CS_VREDRAW;
     wndclass.lpfnWndProc = WndProc;
     wndclass.cbClsExtra = ;
     wndclass.cbWndExtra = ;
     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("Program requires Windows NT!")
             , szAppName, MB_ICONERROR);
         return ;
     }

     hwnd = CreateWindow(szAppName, TEXT("Beeper1 Timer Demo")
         , WS_OVERLAPPEDWINDOW
         , CW_USEDEFAULT, CW_USEDEFAULT
         , CW_USEDEFAULT, CW_USEDEFAULT
         , NULL, NULL, hInstance, NULL);

     ShowWindow(hwnd, nShowCmd);
     UpdateWindow(hwnd);

     while (GetMessage(&msg, NULL, , ))
     {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }

     return msg.wParam;
 }

 LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     switch (message)
     {
     case WM_CREATE:
         SetTimer(hwnd, ID_TIMER, , TimerPorc);
         return ;

     case WM_DESTROY:
         KillTimer(hwnd, ID_TIMER);
         PostQuitMessage();
         return ;
     }

     return DefWindowProc(hwnd, message, wParam, lParam);
 }

 VOID CALLBACK TimerPorc(HWND hwnd, UINT message, UINT iTimerID, DWORD dwTime)
 {
     static BOOL fFlipFlop = FALSE;
     HBRUSH hBrush;
     HDC hdc;
     RECT rc;

     MessageBeep(-);
     fFlipFlop = !fFlipFlop;

     GetClientRect(hwnd, &rc);

     hdc = GetDC(hwnd);
     hBrush = CreateSolidBrush(fFlipFlop ? RGB(, , ) : RGB(, , ));
     FillRect(hdc, &rc, hBrush);
     ReleaseDC(hwnd, hdc);
     DeleteObject(hBrush);
 }

BEEPER2.C