private void ExportExcel(System.Data.DataTable dt)
    {
        System.Web.HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        System.Web.HttpContext.Current.Response.Buffer = false;
        System.Web.HttpContext.Current.Response.Clear();
        System.Web.HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
        System.Web.HttpContext.Current.Response.ClearHeaders();
        System.Web.HttpContext.Current.Response.ContentType = "application/vnd.ms-excel";
        System.Web.HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".xls");

        string sep = "";
        foreach (DataColumn dc in dt.Columns)
        {
            System.Web.HttpContext.Current.Response.Write(sep + dc.ColumnName);
            sep = "\t";
        }
        System.Web.HttpContext.Current.Response.Write("\n");

        int i;
        foreach (DataRow dr in dt.Rows)
        {
            sep = "";
            for (i = 0; i < dt.Columns.Count; i++)
            {
                string mes = dr[i].ToString();
                if (i == 8)
                {
                    mes = " " + dr[i].ToString();
                }

                System.Web.HttpContext.Current.Response.Write(sep + mes);
                sep = "\t";
            }
            System.Web.HttpContext.Current.Response.Write("\n");
        }
        System.Web.HttpContext.Current.Response.End();
    }