asp.net导出txt文件

//通过repeater保存为txt文件 

protected void btn3_Click(object sender, EventArgs e)    {        string sel = "select EX_Parent ,EX_PostCode ,EX_Address  from EnterInfo where EX_Mark like '%" + txtMark3.Text.Trim() + "%'";        DataTable dt = sqlHelper.ExectueTable(sel);//取datatable

        rtInfo.DataSource = dt;        rtInfo.DataBind();        rtInfo.Visible = true;        string str = "";        for (int i = 0; i < this.rtInfo.Items.Count; i++)        {            Label labName = (Label)rtInfo.Items[i].FindControl("labName");            Label labCode = (Label)rtInfo.Items[i].FindControl("labCode");            Label labAddress = (Label)rtInfo.Items[i].FindControl("labAddress");            string vv = labName.Text;            str = str + (vv + ",");            string vv1 = labCode.Text;            str = str + (vv1 + ",");            string vv2 = labAddress.Text;            str = str + vv2;            str = str + ("\r\n");        }        Response.Clear();        Response.Buffer = true;        Response.Charset = "GB2312";        Response.ContentEncoding = System.Text.Encoding.UTF8;        //string val="online;filename=消费明细"+string.Format("{0:yyyyMMddHHmmss}",System.DateTime.Now)+".txt";        Response.AddHeader("Content-Disposition", "attachment;filename=" + Server.UrlEncode("消费明细" + string.Format("{0:yyyyMMddHHmmss}", System.DateTime.Now) + ".txt"));        //指定返回的是一个不能被客户端读取的流，必须被下载           Response.ContentType = "text/plain";        //把文件流发送到客户端           Response.Write(str.ToString());        //停止页面的执行           Response.End();    }