public ViewResult Checkout(Cart cart, ShippingDetails shippingDetails)
 {
     if (!cart.Lines.Any())
     {
         ModelState.AddModelError("", "Sorry, your cart is empty!");
     }
     if (!ModelState.IsValid) return View(shippingDetails);
     _orderProcessor.ProcessOrder(cart, shippingDetails);
     cart.Clear();
     return View("Completed");
 }
 public ViewResult Checkout(Cart cart, ShippingDetails shippingDetails)
 {
     if (cart.lines.Count() == 0)
     {
         ModelState.AddModelError("", "Sorry, your cart is empty!");
     }
     if (ModelState.IsValid)
     {
         orderProcessor.ProcessOrder(cart, shippingDetails);
         cart.Clear();
         return View("Completed");
     }
     else
     {
         return View(shippingDetails);
     }
 }