protected void BtnOrder_Click(object sender, EventArgs e)
{
OfferedPizza offerPizza = HelperSession.GetOfferPizza(Session);
List <Ingredient> listIngredientsSelected = HelperSession.GetListIngredientsSelected(Session);
OrderPizza orderPizza = new OrderPizza(offerPizza.Id_Offered_Pizza, offerPizza.Price, listIngredientsSelected);
List <OrderPizza> listOrdersPizza = HelperSession.GetListOrdersPizza(Session);
listOrdersPizza.Add(orderPizza);
HelperSession.SetListOrdersPizza(Session, listOrdersPizza);
double partialSum = HelperSession.GetSumOrderedPizzas(Session);
partialSum += orderPizza.Price;
HelperSession.SetSumOrderedPizzas(Session, partialSum);
double totalSum = Properties.Settings.Default.PriceDeliveryAndService + partialSum;
HelperSession.SetTotalPriceOrderedPizzas(Session, totalSum);
Response.Redirect("Basket.aspx");
}