从GridView导出到Excel

private void toexcel(string title)
    {
                Response.Clear();
        Response.Buffer = false;
        Response.Charset = "utf-8";
        Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(title) + ".xls");
        Response.ContentEncoding = System.Text.Encoding.UTF8;
        Response.ContentType = "application/ms-excel";
        Response.Write("<meta http-equiv=Content-Type content=\"text/html; charset=utf-8\">");
        this.EnableViewState = false;
        System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
        HtmlTextWriter oHtmlTextWriter = new HtmlTextWriter(oStringWriter);
        GridView1.RenderControl(oHtmlTextWriter);// 数字字符导Excel后转Text格式，否则前面的 0 字符会自动舍弃

        Response.Write(AddExcelHead());
        Response.Write(oStringWriter.ToString());
        Response.Write(AddExcelbottom());
        Response.End();
    }

    protected void btn_toexcel_Click(object sender, EventArgs e)
    {
        toexcel("订单详细");
    }
    public static string AddExcelHead()
    {
        StringBuilder sb = new StringBuilder();
        sb.Append("<html xmlns:x=\"urn:schemas-microsoft-com:office:excel\">");
        sb.Append(" <head>");
        sb.Append(" ");
        sb.Append(" </head>");
        sb.Append("<body>");
        return sb.ToString();
    }
    public static string AddExcelbottom()
    {
        StringBuilder sb = new StringBuilder();
        sb.Append("</body>");
        sb.Append("</html>");
        return sb.ToString();
    }

//重新下面方法解决错误：类型GridView的控件GridView1必须放置在具有runat=server的窗体标记内

public override void VerifyRenderingInServerForm(Control control)
{

}