static void DoUpdate2() { string mode = ""; Console.WriteLine("输入ID"); int id = ReadAInt(); var ois = service.SelectById(id).OrderItems; foreach (var oi in ois) { Console.WriteLine(oi); } Console.WriteLine(@"请选择您的服务: 添加-1 修改-2 删除-3"); mode = Console.ReadLine(); switch (mode) { case "1": Console.WriteLine("输入商品名"); string gName = Console.ReadLine(); Console.WriteLine("输入数量"); int num = ReadAInt(); service.AddItem(id, gName.ToLower(), num); break; case "2": Console.WriteLine("选择要修改的明细"); int index = ReadAInt(); OrderItem uoi = ois[index - 1]; Console.WriteLine("输入商品名"); string gName2 = Console.ReadLine(); Console.WriteLine("输入数量"); int num2 = ReadAInt(); service.UpdateItem(uoi, gName2, num2); break; case "3": Console.WriteLine("选择要删除的明细"); int drop = ReadAInt(); service.DeleteItem(ois, ois[drop - 1]); break; default: break; } }