NHibernet 事务 修改操作，事务没提交，数据库数据却同步（修改）了

public bool UpdateTrainPlanAndPro(TrainPlan trainPlan,List<Pro> pros)
        {
            ISession ss = NHibernateHelper.FrameworkDataProvider.Instance.GetSession();
            ITransaction trans = null;
            using (trans = ss.BeginTransaction())
            {
                try
                {
                    ss.Update(trainPlan);
                    var proList = Session.CreateCriteria<Pro>().Add(Expression.Eq("TId", trainPlan.Id)).List<Pro>();
                    Session.Clear();
                    foreach (var item in proList)
                    {
                        item.StudyHours = trainPlan.TrainHours;
                        item.WorkTypeId = trainPlan.WorkId;
                        ss.Update(item);
                    }
                    trans.Commit();
                    return true;
                }
                catch (Exception e)
                {
                    trans.Rollback();
                    return false;
                }
                finally
                {
                    trans.Dispose();
                }
            }
        }