SQLServer同一实例下事务操作

public bool OrderAdd2(User user, Order order)
        {
            string dbString = ConfigurationManager.ConnectionStrings["TDB"].ConnectionString;
            string db2String = ConfigurationManager.ConnectionStrings["TDB2"].ConnectionString;

            SqlConnection conn = new SqlConnection(dbString);
            SqlConnection conn2 = new SqlConnection(db2String);

            conn.Open();
            conn2.Open();

            SqlTransaction tran = conn.BeginTransaction();
            SqlTransaction tran2 = conn2.BeginTransaction();

            //SqlCommand cmd = conn.CreateCommand();
            //cmd.CommandText = $"insert into [User](USex,UName)values(‘{user.USex}‘,‘{user.UName}‘)";
            //cmd.Transaction = tran;
            //SqlCommand cmd2 = conn2.CreateCommand();
            //cmd2.CommandText = $"insert into [Order](UID,Date)values(‘{order.UID}‘,‘{order.Date}‘)";
            //cmd2.Transaction = tran2;

            string cmdTxt = $"insert into [User](USex,UName)values(@USex,@UName)";
            
            string cmdTxt2 = $"insert into [Order](UID,Date)values(@UID,@Date)";


            try
            {
                //cmd.ExecuteNonQuery();
                //cmd2.ExecuteNonQuery();
                conn.Execute(cmdTxt,user,tran);
                conn2.Execute(cmdTxt2, order, tran2);

                tran.Commit();
                tran2.Commit();
                return true;
            }
            catch (Exception ex)
            {
                tran.Rollback();
                tran2.Rollback();
                return false;
            }
            finally
            {
                conn.Close();
                conn2.Close();
            }
        }