[HttpPost]
        public ActionResult Create(UploadViewItem viewItem, HttpPostedFile postedFile)
        {
            if (!ModelState.IsValid)
            {
                return View();
            }

            var result = AddInstanties(postedFile.InputStream, viewItem.StartDatum, viewItem.EindDatum);
            return View(viewItem);
        }





    public class UploadViewItem : IValidatableObject
    {
        public UploadViewItem()
        {
            EindDatum = DateTime.Now;
            StartDatum = DateTime.Now;
            Result = new UploadResultItem();
        }

        [Required(ErrorMessage = "Bestand kan niet worden gevonden")]
        public string File { get; set; }

        [RegularExpression(@"^(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)\d\d$", ErrorMessage = "Datum moet voldoen aan het volgende format: dd-mm-yyyy")]
        [Required(ErrorMessage = "Startdatum is verplicht")]
        [DisplayName("Startdatum")]
        public DateTime StartDatum { get; set; }

        [RegularExpression(@"^(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)\d\d$", ErrorMessage = "Datum moet voldoen aan het volgende format: dd-mm-yyyy")]
        [Required(ErrorMessage = "Einddatum is verplicht")]
        [DisplayName("Einddatum")]
        public DateTime EindDatum { get; set; }

        public UploadResultItem Result { get; set; }

        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
        {
            if (StartDatum.CompareTo(EindDatum) > 0)
            {
                yield return new ValidationResult("Startdatum moet voor Einddatum zijn", new string[] { "StartDatum", "EindDatum" });
            }
        }
    }

    public class UploadResultItem
    {
        public UploadResultItem()
        {
            FormatErrorLine = 0;
            AmountOfAddedItems = 0;
            WrongCursusInstanties = null;
        }

        public int FormatErrorLine { get; set; }
        public int AmountOfAddedItems { get; set; }
        public WrongCursusDTO[] WrongCursusInstanties { get; set; }
    }