数组 。数据集？？？

Question

我想把读取出来的字段存到数组里（string [] a）应该怎么做public string  QeryList()        {            string str = " ";            string qery = "SELECT Nums from orderList ";            SqlDataReader reader = DBHelper.GetReadData(qery);            if (reader.HasRows)            { reader.Read();                   str += "\n 数量："+reader["Nums"].ToString();                }                     return str;        }