public ActionResult PostTransactionField()
 {
     ViewData["Articles"] = db.Articles.ToList();
     TransactionViewModel newTransaction = new TransactionViewModel();
     return PartialView("_postTransactionField", newTransaction);
 }
        public ActionResult PostTransaction(TransactionViewModel newTransaction)
        {
            if (ModelState.IsValid)
            {
                var article = db.Articles.Find(newTransaction.viewArticleId);
                string articleName = article.articleName;
                decimal articlePrice = article.articlePrice;
                var transactionList = (List<TransactionViewModel>)Session["TransactionList"];
                Session["currentTransactionId"] = (int)Session["currentTransactionId"] + 1;

                newTransaction.viewTransactionId = ((int)Session["currentTransactionId"]);
                newTransaction.viewArticleName = articleName;
                newTransaction.viewPrice = articlePrice;
                transactionList.Add(newTransaction);
            }

            return CurrentTransactions();
        }