public IList<Course> GetAllSelectableCourse(string className, string grade,int studentId)
        {
            IClassGradeCourseDao classGradeCourseDao = new ClassGradeCourseDao(sessionFactory);
            IList<ClassGradeCourse> classGradeCourseList = classGradeCourseDao.GetAllSelectableClassGradeCourse(className, grade);
            ICourseDao courseDao=new CourseDao(sessionFactory);
            for (int i = 0; i < classGradeCourseList.Count; i++) {
                Course closeCourse = courseDao.Get(classGradeCourseList[i].ID.classGradeCourseCourseId);
                //如果这一门课是关闭了,就去掉这个选课关联项
                if (false == closeCourse.courseOpenCloseFlag) {
                    classGradeCourseList.RemoveAt(i);
                    continue;
                }

                //再去掉已经选择的课程,有courseID,年级,专业,课,这门课就不用显示了
                ISelectionDao selectionDao = new SelectionDao(sessionFactory);
                IList<Selection> selectionList = selectionDao.GetSelectionByStudentId(studentId);

                for (int j = 0; j < selectionList.Count; j++)
                {
                    if (selectionList[j].ID.selectionCourseID == classGradeCourseList[i].ID.classGradeCourseCourseId)
                    {
                        classGradeCourseList.RemoveAt(i);
                        continue;
                    }
                }
            }

            IList<Course> selectableCourseList = new List<Course>();

            for (int j = 0; j < classGradeCourseList.Count; j++) {
                Course selectableCourse =courseDao.Get(classGradeCourseList[j].ID.classGradeCourseCourseId);
                selectableCourseList.Add(selectableCourse);
            }
            return selectableCourseList;
        }
 public IList<Course> GetAllSelectedCourse(int studentId)
 {
     ISelectionDao selectionDao = new SelectionDao(sessionFactory);
     IList<Selection> selectedSelectionList=selectionDao.GetSelectionByStudentId(studentId);
     ICourseDao courseDao = new CourseDao(sessionFactory);
     IList<Course> selectedCourseList = new List<Course>();
     for (int i = 0; i < selectedSelectionList.Count;i++ )
     {
         Course selectedCourse=courseDao.Get(selectedSelectionList[i].ID.selectionCourseID);
         selectedCourseList.Add(selectedCourse);
     }
     return selectedCourseList;
 }