aspx導出到excel 無中文亂碼問題

protected void LinkButton1_Click(object sender, EventArgs e)
{

        Response.ClearContent();
        Response.Clear();
        Response.AddHeader("content-disposition", "attachment; filename=sumlate.xls");
        Response.Charset = "GB2312";
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        Response.ContentType = "application/excel";
        System.IO.StringWriter sw = new System.IO.StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        if (GridView1.Rows.Count > 0)
        {
            GridView1.RenderControl(htw);
        }
        else
        {
            GridView1.RenderControl(htw);
        }
        Response.Write(sw.ToString());
        Response.End();



    }

    public override void VerifyRenderingInServerForm(Control control)
    {
        //這個方法不能刪除掉
    }