asp.net excel 导出

  Export("application/ms-excel", "aa.xls");

 Response.Charset = "GB2312";
        Response.ContentEncoding = System.Text.Encoding.UTF7;
        Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(FileName, Encoding.UTF8).ToString());
        Response.ContentType = FileType;
        this.EnableViewState = false;
        StringWriter tw = new StringWriter();
        HtmlTextWriter hw = new HtmlTextWriter(tw);
        GV.RenderControl(hw);
        Response.Write(tw.ToString());
        Response.End();