请教一个delphi的问题

  [ATCObj(csnWSTopNode)]
  TCtrlUnitList = class(TWorkSpaceTreeControl<TSkTreeTopObject>)
  private
    procedure CreateNewSfaaClass(ASender: TObject);
  protected
    procedure InitPopUpMenu(AMenu: TMenuManage); override;
    function HasAttributePage: boolean; override;
  public
    procedure ShowMainPage; override;
  end;中  [ATCObj(csnWSTopNode)]的句话的含义是什么呢？Delphi类