EF架构~通过EF6的DbCommand拦截器来实现数据库读写分离~续~添加事务机制

            ///
            <summary>
            ///
             SQL命令拦截器
    
            ///
            </summary>
            public
            class
             SqlCommandInterceptor : DbCommandInterceptor
    {
        
            ///
            <summary>
            ///
            　读库，从库集群，写库不用设置走默认的EF框架
        
            ///
            </summary>
            string readConn = System.Configuration.ConfigurationManager.AppSettings["readDb"] ?? string.Empty;
        privatestring GetReadConn()
        {
            var readArr = readConn.Split(newchar[] { ‘,‘ }, StringSplitOptions.RemoveEmptyEntries);
            var resultConn = string.Empty;
            if (readArr != null && readArr.Any())
            {
                resultConn = readArr[Convert.ToInt32(Math.Floor((double)new Random().Next(0, readArr.Length)))];
            }
            return resultConn;
        }
        //linq to entity生成的update,deletepublicoverridevoid NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
        {
            base.NonQueryExecuting(command, interceptionContext);//update,delete等写操作直接走主库        }
        ///<summary>/// 执行sql语句，并返回第一行第一列，没有找到返回null,如果数据库中值为null，则返回 DBNull.Value
        ///</summary>///<param name="command"></param>///<param name="interceptionContext"></param>publicoverridevoid ScalarExecuting(DbCommand command,
           DbCommandInterceptionContext<object> interceptionContext)
        {
            if (!string.IsNullOrWhiteSpace(GetReadConn()))//如果配置了读写分离，就去实现            {
                if (!command.CommandText.StartsWith("insert", StringComparison.InvariantCultureIgnoreCase))
                {
                    command.Connection.Close();
                    command.Connection.ConnectionString = GetReadConn();
                    command.Connection.Open();
                }
            }
            base.ScalarExecuting(command, interceptionContext);
        }

        ///<summary>/// linq to entity生成的select,insert
        /// 发送到sqlserver之前触发
        /// warning:在select语句中DbCommand.Transaction为null，而ef会为每个insert添加一个DbCommand.Transaction进行包裹
        ///</summary>///<param name="command"></param>///<param name="interceptionContext"></param>publicoverridevoid ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
        {
            if (!string.IsNullOrWhiteSpace(GetReadConn()))//如果配置了读写分离，就去实现            {
                if (!command.CommandText.StartsWith("insert", StringComparison.InvariantCultureIgnoreCase))
                {
                    command.Connection.Close();
                    command.Connection.ConnectionString = GetReadConn();
                    command.Connection.Open();
                }
            }
            base.ReaderExecuted(command, interceptionContext);
        }
        ///<summary>/// 发送到sqlserver之后触发
        ///</summary>///<param name="command"></param>///<param name="interceptionContext"></param>publicoverridevoid ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
        {
            base.ReaderExecuted(command, interceptionContext);
        }
    }