public ActionResult Create(Article article)
 {
     if (ModelState.IsValid) {
         articleRepository.InsertOrUpdate(article);
         articleRepository.Save();
         return RedirectToAction("Index");
     } else {
         return View();
     }
 }
 public void InsertOrUpdate(Article article)
 {
     if (article.Id == default(int)) {
         // New entity
         context.Articles.Add(article);
     } else {
         // Existing entity
         context.Entry(article).State = EntityState.Modified;
     }
 }