已经编好下面的代码:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=addr.mdb");
            OleDbCommand cmd = new OleDbCommand();
            OleDbDataReader reader;

            cmd.CommandText = " SELECT * FROM addr WHERE Code ='110000'";
            cmd.CommandType = CommandType.Text;
            cmd.Connection = conn;

            conn.Open();

            reader = cmd.ExecuteReader();
            
            if (reader.HasRows)
            {
                MessageBox.Show("find record");
            }
            else
            {
                MessageBox.Show("no record");
            }

            conn.Close();
        }
    }
}

我想把查询得到的结果保存到一个字符串变量中,因为后面要使用查询得到的结果,该如何添加代码?谢谢!