Windows 编程[9] - WM_CLOSE 消息

本例效果图:

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program Project1;usesWindows, Messages;{供 WM_CLOSE 消息调用的自定义过程}
procedure OnClose(h: HWND);
beginif IDOK = MessageBox(h, '确认关闭吗?', '提示', MB_OKCANCEL) thenDestroyWindow(h);
end;function WndProc(wnd: HWND; msg: UINT; wParam: Integer; lParam: Integer): Integer; stdcall;
beginResult := 0;case msg ofWM_CLOSE  : OnClose(wnd); {在收到 WM_CLOSE 消息时调用自定义的 OnClose 过程}WM_DESTROY: PostQuitMessage(0);elseResult := DefWindowProc(wnd, msg, wParam, lParam);end;
end;function RegMyWndClass: Boolean;
varcls: TWndClass;
begincls.style         := CS_HREDRAW or CS_VREDRAW;cls.lpfnWndProc   := @WndProc;cls.cbClsExtra    := 0;cls.cbWndExtra    := 0;cls.hInstance     := HInstance;cls.hIcon         := 0;cls.hCursor       := LoadCursor(0, IDC_ARROW);cls.hbrBackground := HBRUSH(COLOR_WINDOW + 1);cls.lpszMenuName  := nil;cls.lpszClassName := 'MyWnd';Result := RegisterClass(cls) <> 0;
end;{程序入口}
consttit = 'New Form';ws = WS_OVERLAPPEDWINDOW;x = 100; y = 100; w = 300; h = 180;
varhWnd: THandle;Msg : TMsg;
beginRegMyWndClass;hWnd := CreateWindow('MyWnd', tit, ws, x, y, w, h, 0, 0, HInstance, nil);ShowWindow(hWnd, SW_SHOWNORMAL);UpdateWindow(hWnd);while(GetMessage(Msg, 0, 0, 0)) dobeginTranslateMessage(Msg);DispatchMessage(Msg);end;
end.