static void Main(string[] args) { Console.WriteLine("---订单管理系统---"); string operate = ""; while (operate.ToUpper() != "E") { Console.WriteLine(@"请选择您的操作: 查询订单-Q 添加订单-A 更新订单-U 删除订单-D 退出-E"); operate = Console.ReadLine(); switch (operate) { case "Q": DoQuery(); break; case "A": DoAdd(); break; case "U": DoUpdate(); break; case "D": DoDelete(); break; default: operate = "E"; break; } } service.Close(); }