string sql = "select  * from PhoneBook";
        DBHelper.cn.Open();
        SqlCommand cmd = new SqlCommand(sql, DBHelper.cn);
        SqlDataReader reader= cmd.ExecuteReader();
        IList<Phone> list = new List<Phone>();
        Phone ph = new Phone();
        while (reader.Read())
        {
            ph.PhoneId=Convert.ToInt32( reader["PhonIid"]);
            ph.Tel = Convert.ToInt32(reader["Tel"]);
            ph.Address = reader["Address"].ToString();
            ph.Beizhu = reader["Beizhu"].ToString();
            ph.GuanxiId=Convert.ToInt32(reader["GuanxiId"]);
            list.Add(ph);
             
                      }
        GridView1.DataSource = list;
        
               DBHelper.cn.Close();
现在读取不到数据 另外问一下  我这样写代码读取成功了 也只能显示一条数据 高手帮忙