using (TransactionScope trans = new TransactionScope())
            {
                try
                {

                    dbs.Entry<Classroom_Info>(entity);
                    dbs.Set<Classroom_Info>().Add(entity);
                    dbs.SaveChanges();//dbs上下文的SaveChanges

                    //綁定(ding)學生
                    entity.User_Classroom_R.ToList().ForEach(i =>
                    {
                        i.ClassroomInfoID = entity.ClassroomInfoID;
                    });

                    //綁定學生(sheng)
                    entity.User_Classroom_R.ToList().ForEach(i =>
                    {
                        db.Entry<User_Classroom_R>(i);
                        db.Set<User_Classroom_R>().Add(i);
                    });
                    db.SaveChanges();//db上下文的(de)savechanges

                    trans.Complete();//提交事(shi)務
                }
                catch (Exception)
                {
                    trans.Dispose();//出現異(yi)常，事務手動(dong)釋(shi)放
                    throw;
                }
            }