private List <SelectListItem> GetTeacherList()
        {
            var teachers    = _teacherRepository.GetTeacherList();
            var teacherList = new List <SelectListItem>();

            foreach (var teacher in teachers)
            {
                teacherList.Add(new SelectListItem {
                    Text = teacher.EmailAddress, Value = teacher.TeacherId.ToString()
                });
            }

            return(teacherList);
        }