public async Task <IActionResult> Create(CourseClassViewModel model) //[Bind("Id,Title,CourseId")] CourseClass courseClass
        {
            var courseClass = new CourseClass
            {
                Title    = model.Title,
                CourseId = model.CourseId
            };

            courseClass.CourseClassDay = new List <CourseClassDay>();
            model.Days.ToList().ForEach(item =>
            {
                courseClass.CourseClassDay.Add(new CourseClassDay
                {
                    Day        = (Days)item.DayId,
                    StartTime  = item.StartTime,
                    FinishTime = item.FinishTime
                });
            });

            await _context.AddAsync(courseClass);

            await _context.SaveChangesAsync();

            return(RedirectToAction(nameof(Index)));
            //if (ModelState.IsValid)
            //{
            //    _context.Add(courseClass);
            //    await _context.SaveChangesAsync();
            //    return RedirectToAction(nameof(Index));
            //}
            //ViewData["CourseId"] = new SelectList(_context.Courses, "Id", "Title", courseClass.CourseId);
            //return View(courseClass);
            // return View();
        }
        public async Task <IActionResult> CreateAjax(CourseClassViewModel model) //[Bind("Id,Title,CourseId")] CourseClass courseClass
        {
            System.Threading.Thread.Sleep(4000);
            var courseClass = new CourseClass
            {
                Title    = model.Title,
                CourseId = model.CourseId
            };

            courseClass.CourseClassDay = new List <CourseClassDay>();
            model.Days.ToList().ForEach(item =>
            {
                courseClass.CourseClassDay.Add(new CourseClassDay
                {
                    Day        = (Days)item.DayId,
                    StartTime  = item.StartTime,
                    FinishTime = item.FinishTime
                });
            });

            await _context.AddAsync(courseClass);

            await _context.SaveChangesAsync();

            var result = new AjaxActionResult <CourseClass>();

            result.IsSuccess = true;
            result.Message   = "success...";
            return(Ok(result));
        }