【MongoDB学习-在.NET中的简单操作】

1.新建MVC项目， 管理NuGet包，进入下载MongDB.net库文件

2.新增项目DAL数据访问层，引用以下库文件：

3.C# 访问MongoDB通用方法类：

using MongoDB.Driver;
using System;

namespace DAL
{
    public class MongoDb
    {
        public MongoDb(string host,string timeOut)
        {
            this.CONNECT_TIME_OUT = timeOut;
            this.MONGO_CONN_HOST = host;
        }

        /// <summary>
        /// 数据库所在主机
        /// </summary>
        private readonly string MONGO_CONN_HOST;

        /// <summary>
        /// 数据库所在主机的端口
        /// </summary>
        private readonly int MONGO_CONN_PORT = 27017;

        /// <summary>
        /// 连接超时设置 秒
        /// </summary>
        private readonly string CONNECT_TIME_OUT;

        /// <summary>
        /// 数据库的名称
        /// </summary>
        private readonly string DB_NAME = "Mdemo";

        /// <summary>
        /// 得到数据库实例
        /// </summary>
        /// <returns></returns>
        public MongoDatabase GetDataBase()
        {
            MongoClientSettings mongoSetting = new MongoClientSettings();
            //设置连接超时时间
            mongoSetting.ConnectTimeout = new TimeSpan(int.Parse(CONNECT_TIME_OUT) * TimeSpan.TicksPerSecond);
            //设置数据库服务器
            mongoSetting.Server = new MongoServerAddress(MONGO_CONN_HOST, MONGO_CONN_PORT);
            //创建Mongo的客户端
            MongoClient client = new MongoClient(mongoSetting);
            //得到服务器端并且生成数据库实例
            return client.GetServer().GetDatabase(DB_NAME);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DAL
{
    /// <summary>
    /// Mongodb数据库的字段特性  主要是设置索引之用
    /// </summary>
    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
    public class MongoDbFieldAttribute : Attribute
    {
        /// <summary>
        /// 是否是索引
        /// </summary>
        public bool IsIndex { get; set; }

        /// <summary>
        /// 是否是唯一的  默认flase
        /// </summary>
        public bool Unique { get; set; }

        /// <summary>
        /// 是否是升序 默认true
        /// </summary>
        public bool Ascending { get; set; }

        public MongoDbFieldAttribute(bool _isIndex)
        {
            this.IsIndex = _isIndex;
            this.Unique = false;
            this.Ascending = true;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using MongoDB.Driver;
using MongoDB.Bson;
using MongoDB.Driver.Builders;
using System.Reflection;


namespace DAL
{
    /// <summary>
    /// Mongo db的数据库帮助类
    /// </summary>
    public class MongoDbHelper
    {
        /// <summary>
        /// 数据库的实例
        /// </summary>
        private MongoDatabase _db;

        /// <summary>
        /// ObjectId的键
        /// </summary>
        private readonly string OBJECTID_KEY = "_id";

        public MongoDbHelper(string host,string timeOut)
        {
            this._db = new MongoDb(host,timeOut).GetDataBase();
        }

        public MongoDbHelper(MongoDatabase db)
        {
            this._db = db;
        }

        public T GetNextSequence<T>(IMongoQuery query, SortByDocument sortBy, UpdateDocument update, string collectionName,string indexName)
        {
            if (this._db == null)
            {
                return default(T);
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                query = this.InitQuery(query);
                sortBy = this.InitSortBy(sortBy, OBJECTID_KEY);
                update = this.InitUpdateDocument(update, indexName);
                var ido = mc.FindAndModify(query, sortBy, update, true, false);

                return ido.GetModifiedDocumentAs<T>();
            }
            catch (Exception ex)
            {
                return default(T);
            }
        }

        #region 插入数据
        /// <summary>
        /// 将数据插入进数据库
        /// </summary>
        /// <typeparam name="T">需要插入数据的类型</typeparam>
        /// <param name="t">需要插入的具体实体</param>
        public bool Insert<T>(T t)
        {
            //集合名称
            string collectionName = typeof(T).Name;
            return Insert<T>(t, collectionName);
        }

        /// <summary>
        /// 将数据插入进数据库
        /// </summary>
        /// <typeparam name="T">需要插入数据库的实体类型</typeparam>
        /// <param name="t">需要插入数据库的具体实体</param>
        /// <param name="collectionName">指定插入的集合</param>
        public bool Insert<T>(T t, string collectionName)
        {
            if (this._db == null)
            {
                return false;
            }
            try
            {
                MongoCollection<BsonDocument> mc = this._db.GetCollection<BsonDocument>(collectionName);
                //将实体转换为bson文档
                BsonDocument bd = t.ToBsonDocument();
                //进行插入操作
                WriteConcernResult result = mc.Insert(bd);
                if (!string.IsNullOrEmpty(result.ErrorMessage))
                {
                    return false;
                }
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }

        /// <summary>
        /// 批量插入数据
        /// </summary>
        /// <typeparam name="T">需要插入数据库的实体类型</typeparam>
        /// <param name="list">需要插入数据的列表</param>
        public bool Insert<T>(List<T> list)
        {
            //集合名称
            string collectionName = typeof(T).Name;
            return this.Insert<T>(list, collectionName);
        }

        /// <summary>
        /// 批量插入数据
        /// </summary>
        /// <typeparam name="T">需要插入数据库的实体类型</typeparam>
        /// <param name="list">需要插入数据的列表</param>
        /// <param name="collectionName">指定要插入的集合</param>
        public bool Insert<T>(List<T> list, string collectionName)
        {
            if (this._db == null)
            {
                return false;
            }
            try
            {
                MongoCollection<BsonDocument> mc = this._db.GetCollection<BsonDocument>(collectionName);
                //创建一个空间bson集合
                List<BsonDocument> bsonList = new List<BsonDocument>();
                //批量将数据转为bson格式 并且放进bson文档
                list.ForEach(t => bsonList.Add(t.ToBsonDocument()));
                //批量插入数据
                mc.InsertBatch(bsonList);
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }
        #endregion

        #region 查询数据

        #region 查询所有记录
        /// <summary>
        /// 查询一个集合中的所有数据
        /// </summary>
        /// <typeparam name="T">该集合数据的所属类型</typeparam>
        /// <param name="collectionName">指定集合的名称</param>
        /// <returns>返回一个List列表</returns>
        public List<T> FindAll<T>(string collectionName)
        {
            if (this._db == null)
            {
                return null;
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                //以实体方式取出其数据集合
                MongoCursor<T> mongoCursor = mc.FindAll();
                //直接转化为List返回
                return mongoCursor.ToList<T>();
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        /// <summary>
        /// 查询一个集合中的所有数据 其集合的名称为T的名称
        /// </summary>
        /// <typeparam name="T">该集合数据的所属类型</typeparam>
        /// <returns>返回一个List列表</returns>
        public List<T> FindAll<T>()
        {
            string collectionName = typeof(T).Name;
            return FindAll<T>(collectionName);
        }
        #endregion

        #region 查询一条记录
        /// <summary>
        /// 查询索引最大的一条记录
        /// </summary>
        /// <typeparam name="T">该数据所属的类型</typeparam>
        /// <param name="collectionName">去指定查询的集合</param>
        /// <param name="sort">排序字段</param>
        /// <returns>返回一个实体类型</returns>
        public T FindOneToIndexMax<T>(string collectionName, string[] sort)
        {
            return FindOneToIndexMax<T>(null, collectionName, sort);
        }

        /// <summary>
        /// 查询索引最大的一条记录
        /// </summary>
        /// <typeparam name="T">该数据所属的类型</typeparam>
        /// <param name="query">查询的条件 可以为空</param>
        /// <param name="collectionName">去指定查询的集合</param>
        /// <param name="sort">排序字段</param>
        /// <returns>返回一个实体类型</returns>
        public T FindOneToIndexMax<T>(IMongoQuery query,string collectionName, string[] sort)
        {
            if (this._db == null)
            {
                return default(T);
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                query = this.InitQuery(query);
                T t = mc.Find(query).SetSortOrder(SortBy.Descending(sort)).FirstOrDefault<T>();
                return t;
            }
            catch (Exception ex)
            {
                return default(T);
            }
        }
        /// <summary>
        /// 查询一条记录
        /// </summary>
        /// <typeparam name="T">该数据所属的类型</typeparam>
        /// <param name="query">查询的条件 可以为空</param>
        /// <param name="collectionName">去指定查询的集合</param>
        /// <returns>返回一个实体类型</returns>
        public T FindOne<T>(IMongoQuery query, string collectionName)
        {
            if (this._db == null)
            {
                return default(T);
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                query = this.InitQuery(query);
                T t = mc.FindOne(query);
                return t;
            }
            catch (Exception ex)
            {
                return default(T);
            }
        }

        /// <summary>
        /// 查询一条记录
        /// </summary>
        /// <typeparam name="T">该数据所属的类型</typeparam>
        /// <param name="collectionName">去指定查询的集合</param>
        /// <returns>返回一个实体类型</returns>
        public T FindOne<T>(string collectionName)
        {
            return FindOne<T>(null, collectionName);
        }

        /// <summary>
        /// 查询一条记录
        /// </summary>
        /// <typeparam name="T">该数据所属的类型</typeparam>
        /// <returns>返回一个实体类型</returns>
        public T FindOne<T>()
        {
            string collectionName = typeof(T).Name;
            return FindOne<T>(null, collectionName);
        }


        /// <summary>
        /// 查询一条记录
        /// </summary>
        /// <typeparam name="T">该数据所属的类型</typeparam>
        /// <param name="query">查询的条件 可以为空</param>
        /// <returns>返回一个实体类型</returns>
        public T FindOne<T>(IMongoQuery query)
        {
            string collectionName = typeof(T).Name;
            return FindOne<T>(query, collectionName);
        }
        #endregion

        #region 普通的条件查询
        /// <summary>
        /// 根据指定条件查询集合中的数据
        /// </summary>
        /// <typeparam name="T">该集合数据的所属类型</typeparam>
        /// <param name="query">指定的查询条件 比如Query.And(Query.EQ("username","admin"),Query.EQ("password":"admin"))</param>
        /// <param name="collectionName">指定的集合的名称</param>
        /// <returns>返回一个List列表</returns>
        public List<T> Find<T>(IMongoQuery query, string collectionName)
        {
            if (this._db == null)
            {
                return null;
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                query = this.InitQuery(query);
                MongoCursor<T> mongoCursor = mc.Find(query);
                return mongoCursor.ToList<T>();
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        /// <summary>
        /// 根据指定条件查询集合中的数据
        /// </summary>
        /// <typeparam name="T">该集合数据的所属类型</typeparam>
        /// <param name="query">指定的查询条件 比如Query.And(Query.EQ("username","admin"),Query.EQ("password":"admin"))</param>
        /// <returns>返回一个List列表</returns>
        public List<T> Find<T>(IMongoQuery query)
        {
            string collectionName = typeof(T).Name;
            return this.Find<T>(query,collectionName);
        }
        #endregion

        #region 分页查询 PageIndex和PageSize模式  在页数PageIndex大的情况下 效率明显变低

        /// <summary>
        /// 分页查询 PageIndex和PageSize模式  在页数PageIndex大的情况下 效率明显变低
        /// </summary>
        /// <typeparam name="T">所需查询的数据的实体类型</typeparam>
        /// <param name="query">查询的条件</param>
        /// <param name="pageIndex">当前的页数</param>
        /// <param name="pageSize">当前的尺寸</param>
        /// <param name="sortBy">排序方式</param>
        /// <param name="collectionName">集合名称</param>
        /// <returns>返回List列表</returns>
        public List<T> Find<T>(IMongoQuery query, int pageIndex, int pageSize, SortByDocument sortBy, string collectionName)
        {
            if (this._db == null)
            {
                return null;
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                MongoCursor<T> mongoCursor = null;
                query = this.InitQuery(query);
                sortBy = this.InitSortBy(sortBy, OBJECTID_KEY);
                //如页序号为0时初始化为1
                pageIndex = pageIndex == 0 ? 1 : pageIndex;
                //按条件查询 排序 跳数 取数
                mongoCursor = mc.Find(query).SetSortOrder(sortBy).SetSkip((pageIndex - 1) * pageSize).SetLimit(pageSize);
                return mongoCursor.ToList<T>();
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        /// <summary>
        /// 分页查询 PageIndex和PageSize模式  在页数PageIndex大的情况下 效率明显变低
        /// </summary>
        /// <typeparam name="T">所需查询的数据的实体类型</typeparam>
        /// <param name="query">查询的条件</param>
        /// <param name="pageIndex">当前的页数</param>
        /// <param name="pageSize">当前的尺寸</param>
        /// <param name="sortBy">排序方式</param>
        /// <returns>返回List列表</returns>
        public List<T> Find<T>(IMongoQuery query, int pageIndex, int pageSize, SortByDocument sortBy)
        {
            string collectionName = typeof(T).Name;
            return this.Find<T>(query, pageIndex, pageSize, sortBy, collectionName);
        }

        #endregion

        #region 分页查询 指定索引最后项-PageSize模式

        /// <summary>
        /// 分页查询 指定索引最后项-PageSize模式
        /// </summary>
        /// <typeparam name="T">所需查询的数据的实体类型</typeparam>
        /// <param name="query">查询的条件 没有可以为null</param>
        /// <param name="indexName">索引名称</param>
        /// <param name="lastKeyValue">最后索引的值</param>
        /// <param name="pageSize">分页的尺寸</param>
        /// <param name="sortType">排序类型 1升序 -1降序 仅仅针对该索引</param>
        /// <param name="collectionName">指定的集合名称</param>
        /// <returns>返回一个List列表数据</returns>
        public List<T> Find<T>(IMongoQuery query, string indexName, object lastKeyValue, int pageSize, int sortType, string collectionName)
        {
            if (this._db == null)
            {
                return null;
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                MongoCursor<T> mongoCursor = null;
                query = this.InitQuery(query);

                //判断升降序后进行查询
                if (sortType > 0)
                {
                    //升序
                    if (lastKeyValue != null)
                    {
                        //有上一个主键的值传进来时才添加上一个主键的值的条件
                        query = Query.And(query, Query.GT(indexName, BsonValue.Create(lastKeyValue)));
                    }
                    //先按条件查询 再排序 再取数
                    mongoCursor = mc.Find(query).SetSortOrder(new SortByDocument(indexName, 1)).SetLimit(pageSize);
                }
                else
                {
                    //降序
                    if (lastKeyValue != null)
                    {
                        query = Query.And(query, Query.LT(indexName, BsonValue.Create(lastKeyValue)));
                    }
                    mongoCursor = mc.Find(query).SetSortOrder(new SortByDocument(indexName, -1)).SetLimit(pageSize);
                }
                return mongoCursor.ToList<T>();
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        /// <summary>
        /// 分页查询 指定索引最后项-PageSize模式
        /// </summary>
        /// <typeparam name="T">所需查询的数据的实体类型</typeparam>
        /// <param name="query">查询的条件 没有可以为null</param>
        /// <param name="indexName">索引名称</param>
        /// <param name="lastKeyValue">最后索引的值</param>
        /// <param name="pageSize">分页的尺寸</param>
        /// <param name="sortType">排序类型 1升序 -1降序 仅仅针对该索引</param>
        /// <returns>返回一个List列表数据</returns>
        public List<T> Find<T>(IMongoQuery query, string indexName, object lastKeyValue, int pageSize, int sortType)
        {
            string collectionName = typeof(T).Name;
            return this.Find<T>(query, indexName, lastKeyValue, pageSize, sortType, collectionName);
        }

        /// <summary>
        /// 分页查询 指定ObjectId最后项-PageSize模式
        /// </summary>
        /// <typeparam name="T">所需查询的数据的实体类型</typeparam>
        /// <param name="query">查询的条件 没有可以为null</param>
        /// <param name="lastObjectId">上一条记录的ObjectId 没有可以为空</param>
        /// <param name="pageSize">每页尺寸</param>
        /// <param name="sortType">排序类型 1升序 -1降序 仅仅针对_id</param>
        /// <param name="collectionName">指定去查询集合的名称</param>
        /// <returns>返回一个List列表数据</returns>
        public List<T> Find<T>(IMongoQuery query, string lastObjectId, int pageSize, int sortType, string collectionName)
        {
            return this.Find<T>(query, OBJECTID_KEY, new ObjectId(lastObjectId), pageSize, sortType, collectionName);
        }

        /// <summary>
        /// 分页查询 指定ObjectId最后项-PageSize模式
        /// </summary>
        /// <typeparam name="T">所需查询的数据的实体类型</typeparam>
        /// <param name="query">查询的条件 没有可以为null</param>
        /// <param name="lastObjectId">上一条记录的ObjectId 没有可以为空</param>
        /// <param name="pageSize">每页尺寸</param>
        /// <param name="sortType">排序类型 1升序 -1降序 仅仅针对_id</param>
        /// <returns>返回一个List列表数据</returns>
        public List<T> Find<T>(IMongoQuery query, string lastObjectId, int pageSize, int sortType)
        {
            string collectionName = typeof(T).Name;
            return Find<T>(query, lastObjectId, pageSize, sortType, collectionName);
        }

        #endregion


        #endregion

        #region 更新数据

        /// <summary>
        /// 更新数据
        /// </summary>
        /// <typeparam name="T">更新的数据 所属的类型</typeparam>
        /// <param name="query">更新数据的查询</param>
        /// <param name="update">需要更新的文档</param>
        /// <param name="collectionName">指定更新集合的名称</param>
        public bool Update<T>(IMongoQuery query, IMongoUpdate update, string collectionName)
        {
            if (this._db == null)
            {
                return false;
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                query = this.InitQuery(query);
                //更新数据
                WriteConcernResult result = mc.Update(query, update, UpdateFlags.Multi);
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }

        /// <summary>
        /// 更新数据
        /// </summary>
        /// <typeparam name="T">更新的数据 所属的类型</typeparam>
        /// <param name="query">更新数据的查询</param>
        /// <param name="update">需要更新的文档</param>
        public bool Update<T>(IMongoQuery query, IMongoUpdate update)
        {
            string collectionName = typeof(T).Name;
            return this.Update<T>(query, update, collectionName);
        }

        #endregion

        #region 移除/删除数据
        /// <summary>
        /// 移除指定的数据
        /// </summary>
        /// <typeparam name="T">移除的数据类型</typeparam>
        /// <param name="query">移除的数据条件</param>
        /// <param name="collectionName">指定的集合名词</param>
        public bool Remove<T>(IMongoQuery query, string collectionName)
        {
            if (this._db == null)
            {
                return false;
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                query = this.InitQuery(query);
                //根据指定查询移除数据
                mc.Remove(query);
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }

        /// <summary>
        /// 移除指定的数据
        /// </summary>
        /// <typeparam name="T">移除的数据类型</typeparam>
        /// <param name="query">移除的数据条件</param>
        public bool Remove<T>(IMongoQuery query)
        {
            string collectionName = typeof(T).Name;
            return this.Remove<T>(query,collectionName);
        }

        /// <summary>
        /// 移除实体里面所有的数据
        /// </summary>
        /// <typeparam name="T">移除的数据类型</typeparam>
        public bool ReomveAll<T>()
        {
            string collectionName = typeof(T).Name;
            return this.Remove<T>(null,collectionName);
        }

        /// <summary>
        /// 移除实体里面所有的数据
        /// </summary>
        /// <typeparam name="T">移除的数据类型</typeparam>
        /// <param name="collectionName">指定的集合名称</param>
        public bool RemoveAll<T>(string collectionName)
        {
            return this.Remove<T>(null,collectionName);
        }
        #endregion

        #region 创建索引
        /// <summary>
        /// 创建索引
        /// </summary>
        /// <typeparam name="T">需要创建索引的实体类型</typeparam>
        public bool CreateIndex<T>()
        {
            if (this._db == null)
            {
                return false;
            }
            try
            {
                string collectionName = typeof(T).Name;
                MongoCollection<BsonDocument> mc = this._db.GetCollection<BsonDocument>(collectionName);

                PropertyInfo[] propertys = typeof(T).GetProperties(BindingFlags.IgnoreCase | BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty);
                //得到该实体类型的属性
                foreach (PropertyInfo property in propertys)
                {
                    //在各个属性中得到其特性
                    foreach (object obj in property.GetCustomAttributes(true))
                    {
                        MongoDbFieldAttribute mongoField = obj as MongoDbFieldAttribute;
                        if (mongoField != null)
                        {// 此特性为mongodb的字段属性

                            IndexKeysBuilder indexKey;
                            if (mongoField.Ascending)
                            {
                                //升序 索引
                                indexKey = IndexKeys.Ascending(property.Name);
                            }
                            else
                            {
                                //降序索引
                                indexKey = IndexKeys.Descending(property.Name);
                            }
                            //创建该属性
                            mc.CreateIndex(indexKey, IndexOptions.SetUnique(mongoField.Unique));
                        }
                    }
                }
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }
        #endregion

        #region 获取表的行数
        /// <summary>
        /// 获取数据表总行数
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="query"></param>
        /// <param name="collectionName"></param>
        /// <returns></returns>
        public long GetCount<T>(IMongoQuery query,string collectionName)
        {
            if (this._db == null)
            {
                return 0;
            }
            try
            {
                MongoCollection<T> mc = this._db.GetCollection<T>(collectionName);
                if (query == null)
                {
                    return mc.Count();
                }
                else
                {
                    return mc.Count(query);
                }
            }
            catch (Exception ex)
            {
                return 0;
            }
        }
        /// <summary>
        /// 获取数据表总行数
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="query"></param>
        /// <returns></returns>
        public long GetCount<T>(IMongoQuery query)
        {
            string collectionName = typeof(T).Name;
            return GetCount<T>(query,collectionName);
        }

        #endregion

        #region 获取集合的存储大小
        /// <summary>
        /// 获取集合的存储大小
        /// </summary>
        /// <typeparam name="T">该集合对应的实体类</typeparam>
        /// <returns>返回一个long型</returns>
        public long GetDataSize<T>()
        {
            string collectionName = typeof(T).Name;
            return GetDataSize(collectionName);
        }

        /// <summary>
        /// 获取集合的存储大小
        /// </summary>
        /// <param name="collectionName">该集合对应的名称</param>
        /// <returns>返回一个long型</returns>
        public long GetDataSize(string collectionName)
        {
            if (this._db == null)
            {
                return 0;
            }
            try
            {
                MongoCollection<BsonDocument> mc = this._db.GetCollection<BsonDocument>(collectionName);
                return mc.GetTotalStorageSize();
            }
            catch (Exception ex)
            {
                return 0;
            }
        }


        #endregion

        #region 私有的一些辅助方法
        /// <summary>
        /// 初始化查询记录 主要当该查询条件为空时 会附加一个恒真的查询条件，防止空查询报错
        /// </summary>
        /// <param name="query">查询的条件</param>
        /// <returns></returns>
        private IMongoQuery InitQuery(IMongoQuery query)
        {
            if (query == null)
            {
                //当查询为空时 附加恒真的条件 类似SQL：1=1的语法
                query = Query.Exists(OBJECTID_KEY);
            }
            return query;
        }

        /// <summary>
        /// 初始化排序条件  主要当条件为空时 会默认以ObjectId递增的一个排序
        /// </summary>
        /// <param name="sortBy"></param>
        /// <param name="sortByName"></param>
        /// <returns></returns>
        private SortByDocument InitSortBy(SortByDocument sortBy, string sortByName)
        {
            if (sortBy == null)
            {
                //默认ObjectId 递增
                sortBy = new SortByDocument(sortByName, -1);
            }
            return sortBy;
        }

        private UpdateDocument InitUpdateDocument(UpdateDocument update,string indexName)
        {
            if (update == null)
            {
                update = new UpdateDocument("$inc", new QueryDocument(indexName, 0));
            }
            return update;
        }
        #endregion
    }
}

4.调用：先引用库文件：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using MongoDB;
using MongoDbDemo;
using MongoDB.Driver;
using MongoDB.Bson;
using DAL.Entity;
using DAL;
using MongoDB.Driver.Builders;
using System.Diagnostics;

namespace MongoDbDemo.Controllers
{
    public class HomeController : Controller
    {
        //
        // GET: /Home/

        public ActionResult Index()
        {
            return Content("MongoDbDemo");
        }

        #region INSERT
        /// <summary>
        /// 添加用户
        /// </summary>
        /// <returns></returns>
        public ActionResult Ruser()
        {
            try
            {
                string name = Request["name"];
                string age = Request["age"];
                User user1 = new User { Uname = name, Age = age };
                MongoDbHelper mh = new MongoDbHelper("127.0.0.1", "1000");
                if (mh.Insert<User>(user1))
                {
                    return Json(new { success = "true" });
                }
            }
            catch (Exception)
            {
                return Json(new { success = "filled" });
                throw;
            }
            return Json(new { success = "filled" });
        }
        #endregion

        #region SELECT
        /// <summary>
        /// 查询一个集合中的所有数据
        /// </summary>
        /// <returns></returns>
        public ActionResult Seluser()
        {
            MongoDbHelper mh = new MongoDbHelper("127.0.0.1", "1000");
            List<User> users = mh.FindAll<User>();
            return Json(new { success="true"});
        }

        /// <summary>
        /// 按条件查询一条数据
        /// </summary>
        /// <returns></returns>
        public ActionResult SelOne()
        {
            string name = Request["name"];
            string age=Request["age"];
            MongoDbHelper mh = new MongoDbHelper("127.0.0.1", "1000");
            User users = mh.FindOne<User>(Query.And(Query.EQ("Uname", name), Query.EQ("Age", age)));
            return Json(new {success="true" ,users=users});
        }

        /// <summary>
        /// 分页查询
        /// </summary>
        /// <returns></returns>
        public ActionResult SelPage()
        {
            int pageindex=int.Parse(Request["pageindex"]);//页索引
            int pagesize = int.Parse(Request["pagesize"]);//行数
            MongoDbHelper mh = new MongoDbHelper("127.0.0.1", "1000");
            Stopwatch sw1 = new Stopwatch();
            sw1.Start();
            List<User> users = mh.Find<User>(null,pageindex,pagesize,null);
            return Json(new {success="true",users=users });
        }
        #endregion

        #region UPDATE
        /// <summary>
        /// 修改信息
        /// </summary>
        /// <returns></returns>
        public ActionResult upduser()
        {
            MongoDbHelper mh = new MongoDbHelper("127.0.0.1", "1000");
            if (mh.Update<User>(Query.EQ("Uname", "阿斯达"), Update.Set("Uname", "阿斯达s"), "User"))
            {
                return Json(new { success = "true" });
            }
            else
            {
                return Json(new { success = "fales" });
            }

        }
        #endregion

        #region DELETE
        /// <summary>
        /// 删除消息
        /// </summary>
        /// <returns></returns>
        public ActionResult deluser()
        {
            MongoDbHelper mh = new MongoDbHelper("127.0.0.1", "1000");
            if (mh.Remove<User>(Query.EQ("Uname", "阿斯达s")))
            {
                return Json(new { success = "true" });
            }
            else {
                return Json(new { success = "fales" });
            }
        }
        #endregion
    }
}

简单的使用.NET 进行MongoDB的增删改查。