protected void Button4_Click(object sender, EventArgs e)//导出Excel
    {
        
            Response.Clear();
            Response.Buffer = true;
            Response.Charset = "GB2312";
            Response.AppendHeader("Content-Disposition", "attachment;filename=wasteBook" + DateTime.Now.Date.ToString("yyyyMMdd") + ".xls");
            // 如果设置为 GetEncoding("GB2312");导出的文件将会出现乱码！！！
            Response.ContentEncoding = System.Text.Encoding.UTF7;
            Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。
             oStringWriter = new ();
            System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
            //  turn off paging

            StringWriter sw = new StringWriter();
            HtmlTextWriter htw = new HtmlTextWriter(sw);
            this.GridView1.RenderControl(htw);
            string strHtml = sw.ToString().Trim();
            Response.Output.Write(strHtml);
            Response.Flush();
            Response.End();
            // turn the paging on again

      
   
 // GridView1.AllowPaging = true; //删除不用
  // GridView1.DataBind(); //删除不用