C# webservice返回Xml格式文件

string XmlFile = ReturnXml(orgcode, u8no, ex.ToString(), resulttype, "0");
                byte[] bytes = Encoding.UTF8.GetBytes(XmlFile);
                response.BinaryWrite(bytes);

  /// <summary>
        /// 返回NCXML
        /// </summary>
        /// <param name="orgcode">组织编码</param>
        /// <param name="u8no">凭证号</param>
        /// <param name="UTNresultdescription">原因</param>
        /// <param name="resulttype">加锁解锁类型</param>
        /// <returns></returns>
        public string ReturnXml(string orgcode, string u8no, string UTNresultdescription, string resulttype, string resultcode)
        {
            string XmlFile = string.Empty;

            XmlFile = @"<?xml version='1.0' encoding='utf-8'?>
                                                <ufinterface billtype='' filename='' isexchange='' replace='' roottag='' sender='' successful=''>
                                                  <sendresult>                                                         
                                                        <orgcode>" + orgcode + "</orgcode><u8no>" + u8no + "</u8no><resultcode>" + resultcode + "</resultcode><UTNresultdescription>" + UTNresultdescription + "</UTNresultdescription>";
            XmlFile += "         <resulttype>" + resulttype + "</resulttype></sendresult></ufinterface>";

            return XmlFile;
        }