DataContext使用事务

//必须打开连接，用于事务的创建
                if (db.Connection.State == ConnectionState.Closed) db.Connection.Open();
                using (DbTransaction dbtran = db.Connection.BeginTransaction())
                {
                    try
                    {
                        db.Transaction = dbtran;
                        db.SubmitChanges();
                        dbtran.Commit();//提交事务
                    }
                    catch (Exception ex)
                    {
                        dbtran.Rollback();//回滚事务
                    }
                }