拼接xml时出现内存溢出解决办法

 /// designed by Alex

                /// 解决内存溢出问题，不可使用迭代器和foreach

                /// 循环遍历List, 别生成xml，一边释放

                /// 反向遍历，相当于出栈，避免索引顺序乱的问题

                /// 反转List.

                if (zrate.RateList != null && zrate.RateList.Count != 0)

                {

                    log.Debug("反转list");

                    zrate.RateList.Reverse();

                    log.Debug("循环遍历Zrate List 生成xml");

                    int policySize = zrate.RateList.Count;

                    for (int index = policySize - 1; index > -1; index--)

                    {

                        SplitPolicy item = zrate.RateList[index];

                        string strChangePnr = item.IsChangePnr ? "1" : "0";

                        string strCabin = item.Cabin;

                        try

                        {

                            strCabin = strCabin.Replace("/", "");

                        }

                        catch { }

                        decimal c = item.Rate + item.RuleRate;

                        string d = item.IsAutoTicket ? "1" : "0";

                        string strWeekNum = item.WeekNum;

                        if (strWeekNum != "")

                        {

                            strWeekNum = strWeekNum.Replace("/", ",");

                        }

                        string ZtFlightNumber = "";

                        try

                        {

                            ZtFlightNumber = item.ApplyFlightNumber.Replace('/', ',');

                        }

                        catch { }

                        string ZtNoFlightNumber = "";

                        try

                        {

                            ZtNoFlightNumber = item.NotApplyFlightNumber.Replace('/', ',');

                        }

                        catch { }



                        string WorkTimeWeekDay = "";

                        string RefundWorkTimeWeekDay = "";

                        //工作时间

                        for (int i = 0; i < 5; i++)

                        {

                            WorkTimeWeekDay = WorkTimeWeekDay + item.WorkTimeWeekDay + ",";

                            RefundWorkTimeWeekDay = RefundWorkTimeWeekDay + item.RefundTimeWeekDay + ",";

                        }

                        //休息日

                        for (int i = 0; i < 2; i++)

                        {

                            WorkTimeWeekDay = WorkTimeWeekDay + item.WorkTimePlayDay + ",";

                            RefundWorkTimeWeekDay = RefundWorkTimeWeekDay + item.RefundTimePlayDay + ",";

                        }





                        info.Append("<Item Id='" + item.ID + "' State='" + item.Status + "' IsChangePnr='" + strChangePnr + "' ");

                        info.Append("ProviderWorkTime='" + WorkTimeWeekDay.Trim(',') + "' PorviderVWorkTime='" + RefundWorkTimeWeekDay.Trim(',') + "'>");

                        info.Append(item.DepartCode.Replace("/", ",") + "|" + item.ArriveCode.Replace("/", ",") + "|" + item.AirCompany + "|" + item.TripType + "|");

                        info.Append(ZtFlightNumber + "|" + ZtNoFlightNumber + "|" + strWeekNum + "|" + item.TicketType + "|");

                        info.Append(strCabin + "|" + c.ToString("0.000") + "|" + item.SaleBeginTime.ToString("yyyy-MM-dd") + ",");

                        info.Append(item.SaleEndTime.ToString("yyyy-MM-dd") + "|" + item.TravelBeginTime.ToString("yyyy-MM-dd") + ",");

                        info.Append(item.TravelEndTime.ToString("yyyy-MM-dd") + "|" + item.OfficeID + "|");

                        info.Append(item.AddTime.ToString("yyyy-MM-ddTHH:mm:ss.fff") + "|" + item.ModifyTime.ToString("yyyy-MM-ddTHH:mm:ss.fff") + "|");

                        info.Append(item.SupplierCode + "|" + item.Remark + "|" + d);

                        info.Append("</Item>");



                        //同时remove item

                        zrate.RateList.RemoveAt(index);

                        //每10000条调用一次gc，回收前一百条被remove的数据

                        if (0 == index % 10000) { GC.Collect(); } }                 }

                else

                {

                    log.Error("zrate里的RateList为空！");

                }

            }

            else

            {

                info.Append("<OTA_Alter_AirFareRS>");

                info.Append("<Error Code=\"" + zrate.Msg + "\" ShortText=\"" + zrate.Msg + "\" />");

            }

            info.Append("</OTA_Alter_AirFareRS>");



            //WriteLog.WriteErrorLogDataInteraction(info.ToString(), "变动政策返回信息");

            log.Debug("返回xml成功");

            return info.ToString();