[Serializable]
    public  class LessonClassModels
    {
        public long LessonID { get; set; }
        public long ClassID { get; set; }
        public string ClassName { get; set; }
        public int TeacherUIN { get; set; }
        public int LessonsNum { get; set; }
        public long KID { get; set; }
        /// <summary>
        /// 班级的上课时间列表（第一个为上课时间，第二个为下课时间）
        /// </summary>
        public List<KeyValuePair<DateTime, DateTime>> ClassTimeList { get; set; }            
    }

public List<LessonClassModels> GetLessonClassGroupList(long lessonId)
        {
            var repository = RepositoryFactory.GetInstance().GetTaokeRepository();
            IList<LessonClass> lessonClasses = repository.GetAllLessonClassByLessonId(lessonId);
            IEnumerable<IGrouping<long, LessonClass>> groupBy = lessonClasses.GroupBy(u => u.ClassID);

            var list = new List<LessonClassModels>();
            foreach (IGrouping<long, LessonClass> grouping in groupBy)
            {
                var models = new LessonClassModels();
                var classTimeList = new List<KeyValuePair<DateTime, DateTime>>();
                models.ClassID = grouping.Key;
                foreach (LessonClass lessonClass in grouping)
                {
                    models.ClassName = lessonClass.ClassName;
                    models.KID = lessonClass.KID;
                    models.LessonsNum = lessonClass.LessonsNum;
                    models.TeacherUIN = lessonClass.TeacherUIN;
                    var keyPair = new KeyValuePair<DateTime, DateTime>(lessonClass.AttendClassTime, lessonClass.FinishClassTime);
                    classTimeList.Add(keyPair);
                    models.ClassTimeList = classTimeList;
                }
                list.Add(models);
            }
            return list;
        }