Windows程序即使不需要接收使用者输入，也通常具有由菜单上的「About」选项启动的对话框，该对话框用来显示程序的名字、图标、版权旗标和标记为「OK」的按键，也许还会有其它信息（例如技术支持的电话号码）。我们将要看到的第一个程序除了显示一个「About」对话框外，别无它用。这个ABOUT1程序如程序11-1所示：
程序11-1 ABOUT1
ABOUT1.C /*------------------------------------------------------------------------ ABOUT1.C -- About Box Demo Program No. 1 (c) Charles Petzold, 1998 -------------------------------------------------------------------------*/ #include <windows.h> #include "resource.h" LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ; BOOL CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ; int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT ("About1") ; MSG msg ; HWND hwnd ; WNDCLASS wndclass ; wndclass.style = CS_HREDRAW | CS_VREDRAW ; wndclass.lpfnWndProc = WndProc ; wndclass.cbClsExtra = 0 ; wndclass.cbWndExtra = 0 ; wndclass.hInstance = hInstance ; wndclass.hIcon = LoadIcon (hInstance, szAppName) ; wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ; wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ; wndclass.lpszMenuName = szAppName ; wndclass.lpszClassName = szAppName ; if (!RegisterClass (&wndclass)) { MessageBox (NULL, TEXT ("This program requires Windows NT!"), szAppName, MB_ICONERROR) ; return 0 ; } hwnd = CreateWindow (szAppName, TEXT ("About Box Demo Program"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL) ; ShowWindow (hwnd, iCmdShow) ; UpdateWindow (hwnd) ; while (GetMessage (&msg, NULL, 0, 0)) { TranslateMessage (&msg) ; DispatchMessage (&msg) ; } return msg.wParam ; } LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { static HINSTANCE hInstance ; switch (message) { case WM_CREATE : hInstance = ((LPCREATESTRUCT) lParam)->hInstance ; return 0 ; case WM_COMMAND : switch (LOWORD (wParam)) { case IDM_APP_ABOUT : DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ; break ; } return 0 ; case WM_DESTROY : PostQuitMessage (0) ; return 0 ; } return DefWindowProc (hwnd, message, wParam, lParam) ; } BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,WPARAM wParam, LPARAM lParam) { switch (message) { case WM_INITDIALOG : return TRUE ; case WM_COMMAND : switch (LOWORD (wParam)) { case IDOK : case IDCANCEL : EndDialog (hDlg, 0) ; return TRUE ; } break ; } return FALSE ; }