public ActionResult Create(FormCollection collection)
        {
            try
            {
                int codeAdd = Convert.ToInt32(collection["Code"]);
                decimal tauxAdd = Convert.ToDecimal(collection["Taux"]);
                Tva AddTva = new Tva() {Code = codeAdd, Taux = tauxAdd};
                GestionnaireGererTva GesTva = new GestionnaireGererTva();
                GesTva.CreerTva(AddTva);

                return RedirectToAction("Index");
            }
            catch
            {
                return View();
            }
        }