我对Delphi和总体开发还是有些陌生，对于64位开发则真的很陌生。我有来自XE2的32位Delphi App的以下代码，我试图在10.3.3中以64位进行编译。我收到一个无效的Typecast错误，无法找出解决方法。

procedure TSetupDialog.pPkgMethodDefaultSelected;
Var
  ParmNo: integer;
  Choice: PtrRec;
begin
  {Making sure the user selected an actual item.}
  if lbPkgDefault.Itemindex > -1 then
    begin
      Choice := PtrRec(lbPkgDefault.Items.Objects[lbPkgDefault.Itemindex]);{ read object value}<<<<Error
      { don't accept the click if item is disabled }
      if Choice.Hi = 1  then begin {item is disabled}
        messagebeep(0);
        exit;
      end;
      { put the selected parm's choiceNo = Choice.Lo in the Dealer table }
      Quote.pSetPackageUserDefault(Choice.Lo);
    end;
end;

我该如何解决？

编辑：

type
  PtrRec = record  { used for typecasting Stringlist objects,i.e. pointers }
    Lo: smallInt; { 16 bits }
    Hi: smallInt; { 16 bits }
  end;