/// <summary>

        /// FTP删除文件

        /// </summary>

        /// <param name="ftpPath">ftp文件路径</param>

        /// <param name="userId">ftp用户名</param>

        /// <param name="pwd">ftp密码</param>

        /// <param name="fileName">ftp文件名</param>

        /// <returns></returns>

        public string DeleteFile(string ftpPath,string userId,string pwd, string fileName)

        {

            string sRet = "删除成功！";

            FtpWebResponse Respose = null;

            FtpWebRequest reqFTP = null;

            Stream localfile = null;

            Stream stream = null;

            try

            {

                //根据uri创建FtpWebRequest对象

                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(string.Format(@"{0}{1}", ftpPath, fileName)));

                //提供账号密码的验证

                reqFTP.Credentials = new NetworkCredential(userId, pwd);    

                //默认为true是上传完后不会关闭FTP连接

                reqFTP.KeepAlive = false;    

                //执行删除操作

                reqFTP.Method = WebRequestMethods.Ftp.DeleteFile;

                Respose = (FtpWebResponse)reqFTP.GetResponse();

            }

            catch (Exception ex)

            {

                sRet = ex.Message;

            }

            finally

            {

                //关闭连接跟流

                if (Respose != null)

                    Respose.Close();

                if (localfile != null)

                    localfile.Close();

                if (stream != null)

                    stream.Close();

            }

            //返回执行状态

            return sRet;

        }