匯出Excel中文出現亂碼

省前略後~最主要就是~加上紅色部分~
 Response.AddHeader("content-disposition", "attachment;filename=" + DateTime.Now.Ticks + ".xls");
            Response.Charset = "";
            Response.ContentType = "application/vnd.ms-excel";
            Response.Write("<meta http-equiv=Content-Type content=text/html;charset=utf-8>"); 
            StringWriter sw = new StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(sw);

            for (int i = 0; i < gvExcel.Rows.Count; i++)
            {
                gvExcel.Rows[i].Attributes.Add("class", "textmode");
            }