C#操作MongoDB帮助类

        /// <summary>
        /// 获取数据库实例对象
        /// </summary>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <returns>数据库实例对象</returns>
        private static MongoDatabase GetDatabase(string connectionString, string dbName)
        {
            var server = MongoServer.Create(connectionString);
            return server.GetDatabase(dbName);
        }

        /// <summary>
        /// 插入一条记录
        /// </summary>
        /// <typeparam name="T">数据类型</typeparam>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="model">数据对象</param>
        public static void Insert<T>(string connectionString, string dbName, string collectionName, T model) where T : EntityBase
        {
            if (model == null)
            {
                throw new ArgumentNullException("model", "待插入数据不能为空");
            }
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection<T>(collectionName);
            collection.Insert(model);
        }

        /// <summary>
        /// 更新数据
        /// </summary>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="query">查询条件</param>
        /// <param name="dictUpdate">更新字段</param>
        public static void Update(string connectionString, string dbName, string collectionName, IMongoQuery query, 
            Dictionary<string, BsonValue> dictUpdate)
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection(collectionName);
            var update = new UpdateBuilder();
            if (dictUpdate != null && dictUpdate.Count > 0)
            {
                foreach (var item in dictUpdate)
                {
                    update.Set(item.Key, item.Value);
                }
            }
            collection.Update(query, update, UpdateFlags.Multi);
        }

        /// <summary>
        /// 更新数据
        /// </summary>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="query">查询条件</param>
        /// <param name="update">更新条件</param>
        public static void Update(string connectionString, string dbName, string collectionName, IMongoQuery query,
            IMongoUpdate update)
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection(collectionName);
            collection.Update(query, update, UpdateFlags.Multi);
        }

        /// <summary>
        /// 根据ID获取数据对象
        /// </summary>
        /// <typeparam name="T">数据类型</typeparam>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="id">ID</param>
        /// <returns>数据对象</returns>
        public static T GetById<T>(string connectionString, string dbName, string collectionName, string id)
            where T : EntityBase
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection<T>(collectionName);
            var tId = new ObjectId(id);
            return collection.FindOneById(tId);
        }

        /// <summary>
        /// 根据查询条件获取一条数据
        /// </summary>
        /// <typeparam name="T">数据类型</typeparam>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="query">查询条件</param>
        /// <returns>数据对象</returns>
        public static T GetOneByCondition<T>(string connectionString, string dbName, 
            string collectionName, IMongoQuery query)
            where T : EntityBase
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection<T>(collectionName);
            return collection.FindOne(query);
        }

        /// <summary>
        /// 根据查询条件获取多条数据
        /// </summary>
        /// <typeparam name="T">数据类型</typeparam>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="query">查询条件</param>
        /// <returns>数据对象集合</returns>
        public static List<T> GetManyByCondition<T>(string connectionString, string dbName, 
            string collectionName, IMongoQuery query)
            where T : EntityBase
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection<T>(collectionName);
            return collection.Find(query).ToList();
        }

        /// <summary>
        /// 根据查询条件获取多条数据（分页）
        /// </summary>
        /// <typeparam name="T">数据类型</typeparam>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="query">查询条件</param>
        /// <param name="sortBy">排序</param>
        /// <param name="pageIndex">页号</param>
        /// <param name="pageSize">每页大小</param>
        /// <returns>分页数据集合</returns>
        public static PagingList<T> GetManyByPageCondition<T>(string connectionString, string dbName,
            string collectionName, IMongoQuery query, IMongoSortBy sortBy, int pageIndex, int pageSize)
            where T : EntityBase
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection<T>(collectionName);
            var result = new PagingList<T>();
            result.Total = (int)collection.Count(query);
            result.CurrentPageList =
                collection.Find(query).SetSortOrder(sortBy).SetSkip((pageIndex - 1)*pageSize).SetLimit(pageSize).ToList();
            return result;
        }

        /// <summary>
        /// 获取集合中的所有数据
        /// </summary>
        /// <typeparam name="T">数据类型</typeparam>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <returns>数据对象集合</returns>
        public static List<T> GetAll<T>(string connectionString, string dbName, string collectionName)
            where T : EntityBase
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection<T>(collectionName);
            return collection.FindAll().ToList();
        }

        /// <summary>
        /// 删除集合中符合条件的数据
        /// </summary>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        /// <param name="query">查询条件</param>
        public static void DeleteByCondition(string connectionString, string dbName, 
            string collectionName, IMongoQuery query)
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection(collectionName);
            collection.Remove(query);
        }

        /// <summary>
        /// 删除集合中的所有数据
        /// </summary>
        /// <param name="connectionString">数据库连接串</param>
        /// <param name="dbName">数据库名称</param>
        /// <param name="collectionName">集合名称</param>
        public static void DeleteAll(string connectionString, string dbName, string collectionName)
        {
            var db = GetDatabase(connectionString, dbName);
            var collection = db.GetCollection(collectionName);
            collection.RemoveAll();
        }