每个请求设置唯一EFDB

  /// <summary>
        ///     为当前用户创建一个DB对象
        /// </summary>
        public static void CreateCurrentEF()
        {
            MyTalkDBEntities mytalkdb = new MyTalkDBEntities();
            HttpContext.Current.Items[_MyDB] = mytalkdb;
        }

        /// <summary>
        ///     获取当前对象的DB，属性
        /// </summary>
        public static MyTalkDBEntities GetMyDB
        {
            get
            {
                return (MyTalkDBEntities)HttpContext.Current.Items[_MyDB];
            }
        }

        /// <summary>
        ///     销毁当前对象的DB
        /// </summary>
        public static void KillMyDB()
        {
            using (GetMyDB)
            {

            }
        }

//在global中调用
 protected void Application_BeginRequest(object sender, EventArgs e)
        {
            //创建唯一的DB
            WebHelper.CreateCurrentEF();
        }