#region 导出Excel

           Response.Clear();//清除缓冲区流中的所有内容输出。 
            Response.Buffer = true;//该值指示是否缓冲输出，并在完成处理整个响应之后将其发送。 
            Response.ContentType = "application/vnd.ms-excel";//获取或设置输出流的 HTTP MIME 类型为EXCEL类型
            Response.AppendHeader("Content-Disposition", "attachment;filename=" + fileName);//将 HTTP 头添加到输出流。 
            Response.Write("<meta http-equiv=Content-Type content=text/html;charset=utf-8>");
            System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
            System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
            this.RenderControl(oHtmlTextWriter);
            Response.Write(oStringWriter.ToString());
            Response.Flush();
            Response.End();

            #endregion