public ActionResult SelectProductInv(ProductVM p, int Quantity) { if (Quantity == 0) { Quantity = 1; } int? x = HttpContext.Session.GetInt32("Product id"); Product p2 = _strBL.SelectProduct((int)x); p2.quantity += Quantity; int y = p2.quantity; Debug.WriteLine(p2.id); _strBL.UpdateInventory(p2); HttpContext.Session.SetInt32("newQuantity", y); HttpContext.Session.SetInt32("oldQuantity", Quantity); return(View("Updated")); }