static void DoAdd()
{
Console.WriteLine("请输入用户名");
string user = Console.ReadLine();
int id = service.AddOrder(user);
string endOp = "Y";
do
{
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);
Console.WriteLine("是否继续添加Y/N");
endOp = Console.ReadLine();
} while (endOp.ToUpper() == "Y");
Console.WriteLine("订单已创建");
}
