人性化的MongoDb Linq查询方式【带分页】，方便快捷，IQueryable<T>牛逼了、、、C#

十年河东，十年河西，莫欺少年穷

学无止境，精益求精

没什么好说了，主要是代码类的东西，分享给大家

首先，我们创建下基础的分页类库

    public class PaginationListModel<T>
    {
        public PaginationListModel()
        {
            Data = new List<T>();
        }
        public List<T> Data { get; set; }
        public BasePaginationModel Pagination { get; set; }
    }

    public class PaginationModel
    {
        #region 构造函数

        public PaginationModel()
        {
            PageNumber = 1;
            PageSize = 10;
        }

        #endregion
        /// <summary>
        /// 当前页码
        /// </summary>
        public int PageNumber { get; set; }

        /// <summary>
        /// 每页行数
        /// </summary>
        public int PageSize { get; set; }

    }

    /// <summary>
    /// 基本分页实体类
    /// </summary>
    public class BasePaginationModel
    {
        #region 构造函数

        public BasePaginationModel()
        {
            PageNumber = 1;
            PageSize = 10;
        }

        #endregion

        #region 成员

        /// <summary>
        /// 总页数
        /// </summary>
        public int PageCount
        {
            get
            {
                int pages = Total / PageSize;
                int pageCount = Total % PageSize == 0 ? pages : pages + 1;
                return pageCount;
            }
        }

        /// <summary>
        /// 当前页码
        /// </summary>
        public int PageNumber { get; set; }

        /// <summary>
        /// 每页行数
        /// </summary>
        public int PageSize { get; set; }


        /// <summary>
        /// 总记录数
        /// </summary>
        public int Total { get; set; }

        /// <summary>
        /// 总页数
        /// </summary>
        public int Pages { get => PageCount; }

        /// <summary>
        /// 是否首页
        /// </summary>
        public bool IsFirstPage { get => PageNumber == 1; }

        /// <summary>
        /// 是否尾页
        /// </summary>
        public bool IsLastPage { get => PageNumber == Pages; }

        #endregion
    }

其次，我们封装下分页的方法

    public static class MongoPaginationService
    {
        /// <summary>
        /// 支持排序
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="entitys"></param>
        /// <param name="pagination"></param>
        /// <returns></returns>
        public static IQueryable<T> BaseOrderPager<T>(this IOrderedQueryable<T> entitys, ref BasePaginationOrderModel pagination)
        {
            if (pagination != null)
            {
                var result = entitys.GetBasePagination(pagination);
                return result;
            }
            return null;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="pagination"></param>
        /// <returns></returns>
        private static IQueryable<T> GetBasePagination<T>(this IOrderedQueryable<T> source, BasePaginationOrderModel pagination)
        {
            pagination.Total = source.Count();
            return source.Skip((pagination.PageNumber - 1) * pagination.PageSize).Take(pagination.PageSize);
        }

        /// <summary>
        /// 分页
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="entitys"></param>
        /// <param name="json"></param>
        /// <param name="pagination"></param>
        /// <returns></returns>
        public static IQueryable<T> BasePager<T>(this IOrderedQueryable<T> entitys, ref BasePaginationModel pagination)
        {
            if (pagination != null)
            {
                var result = entitys.GetBasePagination(pagination);
                return result;
            }
            return null;
        }

        /// <summary>
        /// 获取分页后的数据
        /// </summary>
        /// <typeparam name="T">实体类型</typeparam>
        /// <param name="source">数据源IQueryable</param>
        /// <param name="pagination">分页参数</param>
        /// <returns></returns>
        private static IQueryable<T> GetBasePagination<T>(this IOrderedQueryable<T> source, BasePaginationModel pagination)
        {
            pagination.Total = source.Count();
            return source.Skip((pagination.PageNumber - 1) * pagination.PageSize).Take(pagination.PageSize);
        }
    }

    public static class PaginationService
    {
        /// <summary>
        /// 分页
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="entitys"></param>
        /// <param name="json"></param>
        /// <param name="pagination"></param>
        /// <returns></returns>
        public static IQueryable<T> BasePager<T>(this IQueryable<T> entitys, ref BasePaginationModel pagination)
        {
            if (pagination != null)
                entitys = entitys.GetBasePagination(pagination);
            return entitys;
        }

        /// <summary>
        /// 获取分页后的数据
        /// </summary>
        /// <typeparam name="T">实体类型</typeparam>
        /// <param name="source">数据源IQueryable</param>
        /// <param name="pagination">分页参数</param>
        /// <returns></returns>
        private static IQueryable<T> GetBasePagination<T>(this IQueryable<T> source, BasePaginationModel pagination)
        {
            pagination.Total = source.Count();
            return source.Skip((pagination.PageNumber - 1) * pagination.PageSize).Take(pagination.PageSize);
        }
    }

最后，我们写个方法来进行查询，如下：

        /// <summary>
        /// 查询设备列表
        /// </summary>
        /// <param name="Data"></param>
        /// <returns></returns>
        [HttpPost]
        public IHttpActionResult SearchBatterys([FromBody] SearchBatteryModel Data)
        {
            BasePaginationModel pagination = new BasePaginationModel()
            {
                PageNumber = Data.PageNumber,
                PageSize = Data.PageSize
            };
            var result = BatteryEchatsService.SearchBatterys(Data,ref pagination);
            return Ok(result);
        }

服务方法：

        public static BaseResponse<PaginationListModel<BatteryHeart2gToTb>> SearchBatterys(SearchBatteryModel data, ref BasePaginationModel Pagination)
        {
            LogstoreDatabaseSettings settings = new LogstoreDatabaseSettings() { LogsCollectionName = CommEnum.MongoDb2gBatteryEnm.Battery2gData.ToString(), DatabaseName = DatabaseName };
            var client = new MongoClient(settings.ConnectionString);
            var database = client.GetDatabase(DatabaseName);
            var Mongo = database.GetCollection<BatteryHeart2gToTb>(settings.LogsCollectionName);
            var q = from p in Mongo.AsQueryable() 
                    select p;

            #region 查询条件
            q = q.Where(A => A.BatterySN.Length==16);
            if (!string.IsNullOrEmpty(data.BatterySN))
            {
                q = q.Where(A => A.BatterySN.Contains(data.BatterySN));
            }
            if (data.minLoopNumber.HasValue)
            {
                q = q.Where(A => A.BatteryLoopNumber>=data.minLoopNumber);
            }
            if (data.maxLoopNumber.HasValue)
            {
                q = q.Where(A => A.BatteryLoopNumber<=data.maxLoopNumber);
            }
            if (data.MinSoc.HasValue)
            {
                q = q.Where(A => A.SOC >= data.MinSoc);
            }
            if (data.MaxSoc.HasValue)
            {
                q = q.Where(A => A.SOC <= data.MaxSoc);
            }
            if (data.BmsStatus.HasValue)
            {
                q = q.Where(A => A.BmsStatus <= data.BmsStatus);
            }
            if (data.online.HasValue)
            {
                var bDate = DateTime.Now.AddHours(-8).AddMinutes(-20);
                //约束条件
                DateTime startTime = new DateTime(bDate.Year, bDate.Month, bDate.Day, bDate.Hour, bDate.Minute, bDate.Second, DateTimeKind.Utc);
              
                if (!data.online.Value)
                {
                    q = q.Where(A => A.CreateTime < startTime);
                }
                else
                {
                    q = q.Where(A => A.CreateTime >= startTime);
                }
            }
            if (data.BmsErrors.Count > 0)
            {
                foreach(var item in data.BmsErrors)
                {
                    switch (item)
                    {
                        case "0": q = q.Where(A => A.err_0== "放电过温保护");break;
                        case "1": q = q.Where(A => A.err_1 == "放电低温保护"); break;
                        case "2": q = q.Where(A => A.err_2 == "总体过压保护"); break;
                        case "3": q = q.Where(A => A.err_3 == "总体欠压保护"); break;
                        case "4": q = q.Where(A => A.err_4 == "单体过压保护"); break;
                        case "5": q = q.Where(A => A.err_5 == "单体欠压保护"); break;
                        case "6": q = q.Where(A => A.err_6 == "短路"); break;
                        case "7": q = q.Where(A => A.err_7 == "绝缘电阻过低"); break;
                        case "8": q = q.Where(A => A.err_8 == "压差过大"); break;
                        case "9": q = q.Where(A => A.err_9 == "进水故障"); break;
                        case "10": q = q.Where(A => A.err_10 == "充电过温保护"); break;
                        case "11": q = q.Where(A => A.err_11 == "充电低温保护"); break;
                        case "12": q = q.Where(A => A.err_12 == "充电过流"); break;
                        case "13": q = q.Where(A => A.err_13 == "放电过流"); break;
                    }
                }
            }
            if (data.cdCn.HasValue)
            {
                q = q.Where(A => A.cdCn == data.cdCn.Value);
            }
            if (data.fdCn.HasValue)
            {
                q = q.Where(A => A.fdCn == data.fdCn.Value);
            }
            #endregion

            var result = PaginationService.BasePager<BatteryHeart2gToTb>(q, ref Pagination);
            PaginationListModel<BatteryHeart2gToTb> M = new PaginationListModel<BatteryHeart2gToTb>()
            {
                Data = result.ToList(),
                Pagination = Pagination
            };
            foreach (var item in M.Data)
            {
                item.CreateTime = item.CreateTime.AddHours(8);
            }
            return CommonBaseResponse.SetResponse<PaginationListModel<BatteryHeart2gToTb>>(M, true);
        }

最最后：

    public class LogstoreDatabaseSettings
    {
        public string ConnectionString { get; set; } = "mongodb://127.0.0.1:27017";//连接字符串
        public string LogsCollectionName { get; set; }
        /// <summary>
        /// 电柜的数据库名称
        /// </summary>
        public string DatabaseName { get; set; } 
    }

就没有了，简单吧。

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