static void Main(string[] args)        {            Console.WriteLine("输入用户编号：");            string cusernum = Console.ReadLine();            Console.WriteLine("输入用户名：");            string cusername = Console.ReadLine();            string connString = @"Data Source=.; Initial Catalog=lh0216; User ID=sa;pwd=Founder123";            //出了using括号objConnection类会被自动释放            using (SqlConnection objConnection = new SqlConnection(connString))            {                objConnection.Open();                               using (SqlCommand objCmd = objConnection.CreateCommand())                {                    objCmd.CommandText = "select * from TBZG where czgbh='" + cusernum + "'" ;                    using (SqlDataReader objReader = objCmd.ExecuteReader())                    {                        //结果集不为空                        if (objReader.Read())                        {                            string cValue = objReader.GetString(objReader.GetOrdinal("czgxm"));                            //检查手工输入的姓名与数据库中查询的名称是否相同                            if (cValue == cusername)                            {                                Console.WriteLine("你好{0}",cusername);                            }                        }                        else                        {                            Console.WriteLine("用户名不存在。");                        }                    }                }            }                        Console.ReadKey();        }