System.IO.StringWriter sw = new System.IO.StringWriter();
            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(sw);
            this.Repeater1.RenderControl(hw);

            Response.Clear();
            Response.ContentType = "application/vnd.ms-excel";
            Response.Charset = "";
            Page.EnableViewState = false;
            string time = DateTime.Now.ToString("yyyyMMddhhmmss");
            Response.AppendHeader("Content-Disposition", "attachment;filename=" + time + ".xls");
            Response.Write(sw.ToString());
            Response.End();


说明：当字符型的数字串导出到excel的时候，经常自动变为科学记数法表示，解决的方法，绑定到Repeater1的时候如此：
<td style="vnd.ms-excel.numberformat:@"><%# DataBinder.Eval(Container.DataItem, "shenfenzheng") %></td>