执行多个lanmada表达式查询

 /// <summary>
        /// 执行多个lanmada表达式查询
        /// </summary>
        /// <typeparam name="T">类型</typeparam>
        /// <param name="row">每页条数</param>
        /// <param name="page">当前页</param>
        /// <param name="total">数据条数</param>
        /// <param name="wherelambdas">lanbda表达式集合</param>
        /// <returns></returns>
        public List<T> SearchByKey<T>(int row,int page,ref int total,List<Func<T, bool>> wherelambdas) where T : class,new()
        {
            //获取所有的数据集合
            List<T> list = LoadEntitiesss<T>(s => true);
            List<T> listNew = new List<T>();
            foreach (Func<T,bool> item in wherelambdas)
            {
               list =  list.Where<T>(item).ToList();
            }

            total = list.Count;//获取总条数
            int start = row * (page - 1);//开始数据
            int end = row * page;//结束数据

            if (total > start)
            {
                end = total < end ? total : end;//判断结束 是否大于数据总条数
                for (int i = start; i < end; i++)
                {
                    listNew.Add(list[i]);
                }
            }

            return listNew;
        }


使用方法:   

SearchByKey() 放在公共方法中   写方法的时候 直接继承

public class WLConfirmEnteringWarehouseOrderBLL : BaseBLL

{

........

}

 /// <summary>
        /// 绑定数据
        /// </summary>
        /// <returns></returns>
        public string GetWLConfirmEnteringWarehouseOrderList()
        {
            string action = ResponseHelper.GetRequestParam("action");
            string first = ResponseHelper.GetRequestParam("first");

            int page = ConvertHelper.ToInt(ResponseHelper.GetRequestParam("page"));
            int row = ConvertHelper.ToInt(ResponseHelper.GetRequestParam("rows"));
            int total = 0;
            if (first.ToLower() == "first")
            {
                return LoadPagerEntities<TPMPurchaseOrder, int>(row, page, s => false, "asc", s => s.purchaseId);
            }
            else
            {
                //客户通知单号
                string custNoticeCode = ResponseHelper.GetRequestParam("custNoticeCode1") == null ? "" : ResponseHelper.GetRequestParam("custNoticeCode1");
                //客户
                string custId = ResponseHelper.GetRequestParam("custId1") == null ? "" : ResponseHelper.GetRequestParam("custId1");
                //内部通知单号
                string innerNoticeCode = ResponseHelper.GetRequestParam("innerNoticeCode1") == null ? "" : ResponseHelper.GetRequestParam("innerNoticeCode1");
                //验收日期
                string checkDateStart = ResponseHelper.GetRequestParam("checkDateStart") == null ? "" : ResponseHelper.GetRequestParam("checkDateStart");
                string checkDateEnd = ResponseHelper.GetRequestParam("checkDateEnd") == null ? "" : ResponseHelper.GetRequestParam("checkDateEnd");
                //上架日期
                string goShelfDateStart = ResponseHelper.GetRequestParam("goShelfDateStart") == null ? "" : ResponseHelper.GetRequestParam("goShelfDateStart");
                string goShelfDateEnd = ResponseHelper.GetRequestParam("goShelfDateEnd") == null ? "" : ResponseHelper.GetRequestParam("goShelfDateEnd");
                //上架确认日期
                string requestConfirmDateStart = ResponseHelper.GetRequestParam("requestConfirmDateStart") == null ? "" : ResponseHelper.GetRequestParam("requestConfirmDateStart");
                string requestConfirmDateEnd = ResponseHelper.GetRequestParam("requestConfirmDateEnd") == null ? "" : ResponseHelper.GetRequestParam("requestConfirmDateEnd");
                //状态
                string status = ResponseHelper.GetRequestParam("status1") == null ? "" : ResponseHelper.GetRequestParam("status1");
                List<Func<TPMPurchaseOrder, bool>> funcList = new List<Func<TPMPurchaseOrder, bool>>();
                #region 条件1
                Func<TPMPurchaseOrder, bool> condition1 = s => true;
                if (custId != "")
                {
                    condition1 = s => s.custId == ConvertHelper.ToInt(custId);
                }
                #endregion
                #region 条件2
                Func<TPMPurchaseOrder, bool> condition2 = s => true;
                if (status == "7")
                {
                    condition2 = s => s.custNoticeCode.Contains(custNoticeCode) && s.innerNoticeCode.Contains(innerNoticeCode) && (s.status == "3" || s.status == "4" || s.status == "5" || s.status == "6");
                }
                else
                {
                    condition2 = s => s.custNoticeCode.Contains(custNoticeCode) && s.innerNoticeCode.Contains(innerNoticeCode) && s.status == status;
                }
                #endregion
                #region 条件3
                //验收日期
                Func<TPMPurchaseOrder, bool> condition3 = s => true;
                if (checkDateStart != "" && checkDateEnd != "")
                {
                    DateTime checkDateStartDate = ConvertHelper.ToDateTime(checkDateStart, "");
                    DateTime checkDateEndDate = ConvertHelper.ToDateTime(checkDateEnd, "");
                    condition3 = s => s.checkDate >= checkDateStartDate && s.checkDate <= checkDateEndDate;
                }
                else if (checkDateStart != "")
                {
                    DateTime checkDateStartDate = ConvertHelper.ToDateTime(checkDateStart, "");
                    condition3 = s => s.checkDate >= checkDateStartDate;
                }
                else if (checkDateEnd != "")
                {
                    DateTime checkDateEndDate = ConvertHelper.ToDateTime(checkDateEnd, "");
                    condition3 = s => s.checkDate <= checkDateEndDate;
                }
                #endregion
                #region 条件4
                Func<TPMPurchaseOrder, bool> condition4 = s => true;
                //上架日期
                if (goShelfDateStart != "" && goShelfDateEnd != "")
                {
                    DateTime goShelfDateStartDate = ConvertHelper.ToDateTime(goShelfDateStart, "");
                    DateTime goShelfDateEndDate = ConvertHelper.ToDateTime(goShelfDateEnd, "");
                    condition4 = s => s.goShelfDate >= goShelfDateStartDate && s.goShelfDate >= goShelfDateEndDate;
                }
                else if (goShelfDateStart != "")
                {
                    DateTime goShelfDateStartDate = ConvertHelper.ToDateTime(goShelfDateStart, "");
                    condition4 = s => s.goShelfDate >= goShelfDateStartDate;
                }
                else if (goShelfDateEnd != "")
                {
                    DateTime goShelfDateEndDate = ConvertHelper.ToDateTime(goShelfDateEnd, "");
                    condition4 = s => s.goShelfDate <= goShelfDateEndDate;
                }
                #endregion
                #region 条件5
                Func<TPMPurchaseOrder, bool> condition5 = s => true;
                //上架确认日期
                if (requestConfirmDateStart != "" && requestConfirmDateEnd != "")
                {
                    DateTime requestConfirmDateStartDate = ConvertHelper.ToDateTime(requestConfirmDateStart, "");
                    DateTime requestConfirmDateEndDate = ConvertHelper.ToDateTime(requestConfirmDateEnd, "");
                    condition5 = s => s.requestGoShelfDate >= requestConfirmDateStartDate && s.requestGoShelfDate <= requestConfirmDateEndDate;
                }
                else if (requestConfirmDateStart != "")
                {
                    DateTime requestConfirmDateStartDate = ConvertHelper.ToDateTime(requestConfirmDateStart, "");
                    condition5 = s => s.requestGoShelfDate >= requestConfirmDateStartDate;
                }
                else if (requestConfirmDateEnd != "")
                {
                    DateTime requestConfirmDateEndDate = ConvertHelper.ToDateTime(requestConfirmDateEnd, "");
                    condition5 = s => s.requestGoShelfDate <= requestConfirmDateEndDate;
                }
                #endregion
                funcList.Add(condition1);
                funcList.Add(condition2);
                funcList.Add(condition3);
                funcList.Add(condition4);
                funcList.Add(condition5);
                List<TPMPurchaseOrder> tPMPurchaseOrderList = SearchByKey<TPMPurchaseOrder>(row, page, ref total, funcList);
                string r = JsonHelper.JsonSerialize(tPMPurchaseOrderList);
                return ResponseHelper.ResponseJson(total.ToString(), r);
            }
        }

  

原文地址:https://www.cnblogs.com/jiao28/p/4012974.html