public ActionResult AgregarListaEsperaFactura(ArticuloStock a)
        {
            List <ArticuloStock> lista = (List <ArticuloStock>)Session["lista"];

            if (a.stock < 1)
            {
                return(Json(new { success = false, cambio = true }, JsonRequestBehavior.AllowGet));
            }
            if (rc.Stock_Producto(a.id) - a.stock < 0)
            {
                return(Json(new { success = false, cambio = false }, JsonRequestBehavior.AllowGet));
            }
            Boolean cambio;

            if (rc.Stock_Producto(a.id) - a.stock <= ac.Buscar(a.id).miniStock)
            {
                cambio = false;
            }
            else
            {
                cambio = true;
            }
            foreach (ArticuloStock art in lista)
            {
                if (art.id == a.id)
                {
                    art.precio = a.precio;
                    art.stock  = a.stock;
                    return(Json(new { success = true, data = a, modificar = true, cambio }, JsonRequestBehavior.AllowGet));
                }
            }
            lista.Add(a);
            return(Json(new { success = true, data = a, modificar = false, cambio }, JsonRequestBehavior.AllowGet));
        }
        public ActionResult BorrarListaEsperaFactura(ArticuloStock a)
        {
            List <ArticuloStock> lista = (List <ArticuloStock>)Session["lista"];

            foreach (ArticuloStock art in lista)
            {
                if (art.id == a.id)
                {
                    lista.Remove(art);
                    break;
                }
            }
            return(Json(new { success = true, data = a }, JsonRequestBehavior.AllowGet));
        }