ditDirectory未定义，莫名奇妙啊

Delphi(Pascal) code

unit sync;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient,  IdFTP, StdCtrls, RzButton;type  TForm1 = class(TForm)    FTPClient: TIdFTP;    RzBitBtn1: TRzBitBtn;    procedure RzBitBtn1Click(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;const  Model = 'yyyy/mm/dd,hh:mm:ss';var  Form1: TForm1;implementation{$R *.dfm}procedure FindRemoteDir(var idFTP: TIdFtp; RemoteDir: string; var filename,  filesize, filetime: Tstrings);var  i, DirCount: integer;  sName: string;begin  idFTP.RetrieveCurrentDir;  idFTP.ChangeDir(RemoteDir);  idFTP.List(nil);  DirCount := idFTP.DirectoryListing.Count;  if DirCount = 0 then  begin    idFTP.ChangeDirUp;    idFTP.List(nil);    Exit;  end;  for i := 0 to DirCount - 1 do  begin    if DirCount <> idFTP.DirectoryListing.Count then    begin      repeat        idFTP.ChangeDirUp;        idFTP.List(nil);        Application.ProcessMessages;      until DirCount = idFTP.DirectoryListing.Count;      Exit;    end;   if  idFTP.DirectoryListing.Items[i].ItemType = ditDirectory then//这句编译不过，提示ditDirectory未定义       Remotefindall(idFTP, idFTP.RetrieveCurrentDir + '\' + idFTP.DirectoryListing.Items[i].FileName, filename, filesize, filetime)    else    begin       sName := RemoteDir + '\' + idFTP.DirectoryListing.Items[i].FileName;      sName := MidStr(sName, iwidth + 1, length(sName) - iwidth + 1);      filename.add(sName);      filesize.add(inttostr(idFTP.DirectoryListing.Items[i].Size));      filetime.Add(FormatDateTime(Model, idFTP.DirectoryListing.Items[i].ModifiedDate));    end;  end;  Application.ProcessMessages;  if i = DirCount - 1 then  begin    idFTP.ChangeDirUp;    idFTP.List(nil);  end;end;procedure TForm1.RzBitBtn1Click(Sender: TObject);begin  FTPClient.Username := 'Login=tranuser';  FTPClient.Password := '8653635';  FTPClient.Port := 21;  FTPClient.Connect();end;end.