public ActionResult New()
        {
            var classInfo      = _context.ClassInfos.ToList();
            var sectionInfo    = _context.Sections.ToList();
            var departmentInfo = _context.Departments.ToList();

            var viewModel = new ClassFromViewModel
            {
                Class       = new Class(),
                ClassInfos  = classInfo,
                Sections    = sectionInfo,
                Departments = departmentInfo
            };

            return(View("ClassForm", viewModel));
        }
        public ActionResult Details(int id)
        {
            var activeStudent =
                _context.StudentClasses.Where(c => c.ClassId == id).Where(c => c.IsActive).Select(c => c.StudentId);

            var viewData = new ClassFromViewModel
            {
                Class          = _context.Classes.Include(c => c.ClassInfo).Include(c => c.Department).Include(c => c.Section).SingleOrDefault(c => c.Id == id),
                ClassSubject   = _context.ClassSubjects.Include(c => c.Subject).Where(c => c.ClassId == id).ToList(),
                StudentClasses = _context.StudentClasses.Include(c => c.Student).Where(c => c.ClassId == id).Where(c => c.IsActive).ToList()
            };



            if (viewData.Class == null)
            {
                return(HttpNotFound());
            }

            return(View(viewData));
        }
        public ActionResult Save(Class classes)
        {
            if (!ModelState.IsValid)
            {
                var viewModel = new ClassFromViewModel
                {
                    Class       = classes,
                    ClassInfos  = _context.ClassInfos.ToList(),
                    Sections    = _context.Sections.ToList(),
                    Departments = _context.Departments.ToList()
                };

                return(View("ClassForm", viewModel));
            }
            else
            {
                _context.Classes.Add(classes);
            }


            _context.SaveChanges();

            return(RedirectToAction("Index", "Class"));
        }