List<OrderItem> oiList = new List<OrderItem>();
for (PricebookEntry pbe : List<PricebookEntry>)standardSetController.getRecords()) {
                OrderItem oi = new OrderItem();
                oi.UnitPrice = pbe.UnitPrice;
                oi.PricebookEntryId = pbe.Id;
                oi.Product2Id = pbe.Product2Id;
                oi.Quantity = 0;
                oi.Product2 = pbe.Product2;
                oiList.add(oi);
                system.debug('orderExtension - getOrderItemList - oi = ' + oi);
            }