static void Main(string[] args)
{
OrderService os = new OrderService();
Console.Write("添加订单请输入1；删除订单请输入2；修改订单请输入3；查询订单请输入4.");
int choose = Int32.Parse(Console.ReadLine());
switch (choose)
{
case 1:
{
os.AddOrder();
break;
}
case 2:
{
os.DeleteOrder();
break;
}
case 3:
{
os.ModifyOrder();
break;
}
case 4:
{
os.SearchOrder();
break;
}
}
}