public ActionResult New()
        {
            var classes          = _context.Classes.ToList();
            var departments      = _context.Departments.ToList();
            var subjectViewModel = new SubjectFormViewModel()
            {
                Classes     = classes,
                Departments = departments
            };

            return(View("SubjectForm", subjectViewModel));
        }
        public ActionResult Edit(int id)
        {
            var subject = _context.Subjects.SingleOrDefault(c => c.SubjectId == id);

            if (subject == null)
            {
                return(HttpNotFound());
            }
            var subjectViewModel = new SubjectFormViewModel()
            {
                Subject     = subject,
                Classes     = _context.Classes.ToList(),
                Departments = _context.Departments.ToList()
            };

            return(View("SubjectForm", subjectViewModel));
        }