Windows 編程[11] – WM_SIZE 訊息

本例:

program Project1;uses  Windows, Messages;{供 WM_SIZE 訊息調用的自訂過程}procedure OnSize(h: HWND);var  Rect: TRect;  pt: TPoint;  buf: array[0..255] of Char;begin  GetWindowRect(h, Rect);                  {擷取視窗矩形}  pt.X := Rect.Right - Rect.Left;          {提取寬度}  pt.Y := Rect.Bottom - Rect.Top;          {提取高度}  wvsprintf(buf, '寬度:%d, 高度:%d', @pt);  {格式化到緩衝區}  SetWindowText(h, buf);                   {顯示在標題}end;function WndProc(wnd: HWND; msg: UINT; wParam: Integer; lParam: Integer): Integer; stdcall;begin  Result := 0;  case msg of    WM_SIZE    : OnSize(wnd);       {改變視窗大小的訊息}    WM_DESTROY : PostQuitMessage(0);  else    Result := DefWindowProc(wnd, msg, wParam, lParam);  end;end;function RegMyWndClass: Boolean;var  cls: TWndClass;begin  cls.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;{程式入口}const  tit = 'New Form';  ws = WS_OVERLAPPEDWINDOW;  x = 100; y = 100; w = 300; h = 180;var  hWnd: THandle;  Msg : TMsg;begin  RegMyWndClass;  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)) do  begin    TranslateMessage(Msg);    DispatchMessage(Msg);  end;end.