！重赏之上必有勇夫，求教c# ftp怎么判断目录上取出来的东西是文件还是文件夹！

   public string[] GetFileList()
        {
            string[] downloadFiles;
            StringBuilder result = new StringBuilder();
            FtpWebRequest reqFTP;
            try
            {
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpPath + "/"));
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(username,
                                                           password);
                reqFTP.Method = WebRequestMethods.Ftp.ListDirectory;
                WebResponse response = reqFTP.GetResponse();
                StreamReader reader = new StreamReader(response
                                                .GetResponseStream());

                string line = reader.ReadLine();
                while (line != null)
                {
                    result.Append(line);
                    result.Append("\n");
                    line = reader.ReadLine();
                }
                // to remove the trailing '\n'
                result.Remove(result.ToString().LastIndexOf('\n'), 1);
              
              
                reader.Close();
                response.Close();
                return result.ToString().Split('\n');
            }
            catch (Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
                downloadFiles = null;
                return downloadFiles;
            }
        }