public IActionResult OnPost(string endBookingDate, string startBookingDate, int carId) { if (ModelState.IsValid) { startBookingDate = CarRepository.ChangeDateFormatToDaysMonthYears(startBookingDate); endBookingDate = CarRepository.ChangeDateFormatToDaysMonthYears(endBookingDate); if (Convert.ToDateTime(startBookingDate).Date.CompareTo(DateTime.Now.Date) >= 0) { var availableDays = CarRepository.AvailableDays(startBookingDate, endBookingDate, carId); if (availableDays != null) { if (!availableDays.Any(c => c.Value == "Not Available")) { return(RedirectToPage("booking", new { area = "Cars", EndBookingDate = endBookingDate, StartBookingDate = startBookingDate, CarId = carId })); } else { TempData["avilabeldays"] = availableDays; return(OnGet(carId)); } } } TempData["DateIsNotCorrect"] = true; } TempData["DateIsNotCorrect"] = true; return(OnGet(carId)); }