/// <summary>
    /// MongoDB帮助类
    /// </summary>
    public class MongoDBHelper
    {
        /// <summary>
        /// 数据库连接字符串
        /// </summary>
        private const string strconn = "mongodb://127.0.0.1:27017";

        /// <summary>
        /// 数据库名称
        /// </summary>
        private const string dbName = "pxdnet";

        MongoServer server = new MongoClient(strconn).GetServer();

        static MongoDatabase db;

        /// <summary>
        /// 构造函数
        /// </summary>
        public MongoDBHelper()
        {
            if(db == null)
            {
                db = server.GetDatabase(dbName);
            }
        }

        /// <summary>
        /// 获取数据库
        /// </summary>
        /// <returns></returns>
        public static MongoDatabase GetDB()
        {
            return new MongoClient(strconn).GetServer().GetDatabase(dbName);
        }

        /// <summary>
        /// 新增
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="entity"></param>
        public static T Add<T>(T entity)
        {
            var col = GetDB().GetCollection(typeof(T).Name);
            col.Insert<T>(entity);
            return entity;
        }

        /// <summary>
        /// 编辑
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="entity"></param>
        /// <param name="id"></param>
        public static void Update<T>(T entity, ObjectId id)
        {
            var col = GetDB().GetCollection(typeof(T).Name);

            BsonDocument bsd = BsonExtensionMethods.ToBsonDocument(entity);

            IMongoQuery query = Query.EQ("_id", id);

            col.Update(query, new UpdateDocument(bsd));
        }

        /// <summary>
        /// 删除
        /// remark:条件删除
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="dics"></param>
        public static void Delete<T>(Dictionary<string, object> dics)
        {
            var col = GetDB().GetCollection(typeof(T).Name);

            var query = new QueryDocument(dics);

            var result = col.Remove(query);
        }

        /// <summary>
        /// 删除
        /// remark:根据ObjectId删除
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="id"></param>
        public static void Delete<T>(ObjectId id)
        {
            var col = GetDB().GetCollection(typeof(T).Name);
            IMongoQuery query = Query.EQ("_id", id);
            col.Remove(query);
        }

        /// <summary>
        /// 查询全部
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static List<T> QueryList<T>()
        {
            var col = GetDB().GetCollection(typeof(T).Name);

            var result = col.FindAllAs<T>();

            return result.ToList<T>();
        }

        /// <summary>
        /// 根据条件查询
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="dics"></param>
        /// <returns></returns>
        public static List<T> QueryList<T>(Dictionary<string,object> dics)
        {
            var col = GetDB().GetCollection(typeof(T).Name);
            var query = new QueryDocument(dics);

            var result = col.FindAs<T>(query);

            return result.ToList<T>();
        }
    }