第八章 计时器（BEEPER1）

 *-------------------------------------
     BEEPER1.C -- Timer Demo Program No.
     (c) Charles Petzold,
     -------------------------------------*/

 #include <Windows.h>

 #define ID_TIMER 1

     LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

 int WINAPI WinMain( __in HINSTANCE hInstance
     , __in_opt HINSTANCE hPrevInstance
     , __in LPSTR lpCmdLine
     , __in int nShowCmd )
 {
     static TCHAR szAppName[] = TEXT("Bepper1");
     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)
 {
     static BOOL fFlipFlop = FALSE;
     HBRUSH hBrush;
     HDC hdc;
     PAINTSTRUCT ps;
     RECT rc;

     switch (message)
     {
     case WM_CREATE:
         SetTimer(hwnd, ID_TIMER, , NULL);
         return ;

     case WM_TIMER:
         MessageBeep(-);
         fFlipFlop = !fFlipFlop;
         InvalidateRect(hwnd, NULL, FALSE);
         return ;

     case WM_PAINT:
         hdc = BeginPaint(hwnd, &ps);

         GetClientRect(hwnd, &rc);
         hBrush = CreateSolidBrush(fFlipFlop ? RGB(, , ) : RGB(, , ));
         FillRect(hdc, &rc, hBrush);

         EndPaint(hwnd, &ps);
         DeleteObject(hBrush);
         return ;

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

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

BEEPER1.C