Mongodb for C# 分组查询

#region 排序获取集合 static List<BsonDocument> GetPagerWithGroup(string connectionString, string databaseName,      string collectionName, IMongoQuery param, GroupByBuilder groupByBuilder, PageInfo info, out int pageCount)

        /// <summary>

        ///分组查询获取集合

        /// </summary>

        /// <param name="connectionString">数据库连接字符串</param>

        /// <param name="databaseName">数据库名称</param>

        /// <param name="collectionName">集合名称</param>

        /// <param name="param">条件</param>

        /// <param name="groupByBuilder">分组条件</param>

        /// <param name="info">分页信息</param>

        /// <param name="pageCount">总页数</param>

        /// <returns>List</returns>

        public static List<BsonDocument> GetPagerWithGroup(string connectionString, string databaseName,

            string collectionName, IMongoQuery param, GroupByBuilder groupByBuilder, PageInfo info, out int pageCount)

        {



            var collection = GetMongoCollection<BsonDocument>(connectionString, databaseName, collectionName);

            var dictionary = new Dictionary<string, int>();

            dictionary["num"] = 0;

            List<BsonDocument> list = null;

            var q = collection.Group(param, groupByBuilder, BsonDocument.Create(dictionary),

                BsonJavaScript.Create("function(doc,prev){prev.num++;}"),

                BsonJavaScript.Create("function(doc){ doc.count=doc.num;delete doc.num; }"));

        

            pageCount = 0;

            if (info == null)

            {

                list = q.ToList();

            }

            else

            {

                list = q

            .Skip((info.PageIndex - 1) * info.PageSize).Take(info.PageSize).ToList();

                var count = q.Count();

                if (count <= 0)

                {

                    pageCount = 0;

                    return null;

                }

                pageCount = (int)(count % info.PageSize == 0 ? count / info.PageSize : (count / info.PageSize) + 1);

            }



            return list;

        }

        #endregion