FTP文件操作之删除文件

/// <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;
        }