public ActionResult Create(BorrowCreateViewModel model) { if (model.ChoosenBooks.Contains(-1)) { ModelState.AddModelError("emptyBook", "Each list must have a book selected"); } if (model.ChoosenBooks.Length != model.ChoosenBooks.Distinct().Count()) { ModelState.AddModelError("haveDuplicate", "It isn't possible to borrow two identical books."); } if (!ModelState.IsValid) { var errorList = (from item in ModelState where item.Value.Errors.Any() select item.Value.Errors[0].ErrorMessage).ToList(); return(Json(new { success = false, errors = errorList }, JsonRequestBehavior.AllowGet)); } borrowService.InsertBorrows(model); return(Json(new { success = true }, JsonRequestBehavior.AllowGet)); }