指针的妙用

请看VCL源代码，下面的代码相信大家都看得懂，我就不解释了。
procedure TCustomListBox.CreateParams(var Params: TCreateParams);
type
  PSelects = ^TSelects;
  TSelects = array[Boolean] of DWORD;
const
  Styles: array[TListBoxStyle] of DWORD =
    (0, LBS_OWNERDRAWFIXED, LBS_OWNERDRAWVARIABLE);
  Sorteds: array[Boolean] of DWORD = (0, LBS_SORT);
  MultiSelects: array[Boolean] of DWORD = (0, LBS_MULTIPLESEL);
  ExtendSelects: array[Boolean] of DWORD = (0, LBS_EXTENDEDSEL);
  IntegralHeights: array[Boolean] of DWORD = (LBS_NOINTEGRALHEIGHT, 0);
  MultiColumns: array[Boolean] of DWORD = (0, LBS_MULTICOLUMN);
  TabStops: array[Boolean] of DWORD = (0, LBS_USETABSTOPS);
  CSHREDRAW: array[Boolean] of DWORD = (CS_HREDRAW, 0);
var
  Selects: PSelects;
begin
  inherited CreateParams(Params);
  CreateSubClass(Params, 'LISTBOX');
  with Params do
  begin
    Selects := @MultiSelects;
    if FExtendedSelect then Selects := @ExtendSelects;
    Style := Style or (WS_HSCROLL or WS_VSCROLL or LBS_HASSTRINGS or
      LBS_NOTIFY) or Styles[FStyle] or Sorteds[FSorted] or
      Selects^[FMultiSelect] or IntegralHeights[FIntegralHeight] or
      MultiColumns[FColumns <> 0] or BorderStyles[FBorderStyle] or
      TabStops[FTabWidth <> 0];
    if NewStyleControls and Ctl3D and (FBorderStyle = bsSingle) then
    begin
      Style := Style and not WS_BORDER;
      ExStyle := ExStyle or WS_EX_CLIENTEDGE;
    end;
    WindowClass.style := WindowClass.style and not (CSHREDRAW[UseRightToLeftAlignment] or CS_VREDRAW);
  end;
end;