Excel导出 中文文件名乱码

   Response.Clear();
        Response.Buffer = true;
        Response.Charset = "GB2312";
     // Response.Charset = "UTF-8";

        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312"); //System.Text.Encoding.UTF8;;//设置输出流为简体中文
       Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。
      // Response.AppendHeader("Content-Disposition", "attachment;filename=" + str);
       Response.AddHeader("Content-Disposition", "attachment;   filename=" + System.Web.HttpUtility.UrlEncode(str, System.Text.Encoding.UTF8) + ".xls");//这样的话，可以设置文件名为中文，且文件名不会乱码。其实就是将汉字转换成UTF8

      EnableViewState = false;
      Response.Write(data);
      Response.End();