public class ExcelHelper
    {
        //导出csv格式
        public static void ExportToCSV(Page page, DataTable dt, string FileName)
        {
            System.Web.HttpResponse resp;
            resp = page.Response;
            resp.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
            resp.HeaderEncoding = System.Text.Encoding.GetEncoding("GB2312");

            resp.AddHeader("Content-Disposition", "attachment; filename=" +System.Web.HttpUtility.UrlEncode(FileName) + ".csv");
            resp.ContentType = "application/ms-excel";
            StringWriter sw = new StringWriter();
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                sb.Append(dt.Columns[i].ColumnName);
                if (i != dt.Columns.Count - 1)
                {
                    sb.Append(",");
                }
            }
            sw.WriteLine(sb.ToString());
            foreach (DataRow dr in dt.Rows)
            {
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    sw.Write(dr[i].ToString().Replace("<br/>", "，"));
                    if (i != dt.Columns.Count - 1)
                    {
                        sw.Write(",");
                    }

                }
                resp.Write(sw);
                sw.WriteLine("");
                //sw.WriteLine("");
            }
         //   sw.Close();
          //  resp.Clear();
            resp.Write(sw);
            resp.End();
        }
}