DataSet to Excel

private void toexcel(DataSet ds, string title)
    {
        StringBuilder sb = new StringBuilder();
        Response.Clear();
        Response.Buffer = false;
        Response.Charset = "GB2312";
        Response.AppendHeader("Content-Disposition", "attachment;filename=" + title + ".xls");
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        Response.ContentType = "application/ms-excel";
        Response.Write("<meta http-equiv=Content-Type content=\"text/html; charset=GB2312\">");
        this.EnableViewState = false;
        System.Data.DataTable table = ds.Tables[0];
        sb.Append("<table border=1>\n");
        sb.Append("<tr>\n");
        foreach (DataColumn col in table.Columns)
        {
            sb.Append("<td>");
            sb.Append(col.ColumnName);
            sb.Append("</td>\n");

        }
        sb.Append("</tr>\n");

        foreach (DataRow row in table.Rows)
        {
            sb.Append("<tr>\n");
            foreach (DataColumn col in table.Columns)
            {
                sb.Append("<td>");
                sb.Append(row[col.ColumnName].ToString());
                sb.Append("</td>\n");
            }
            sb.Append("</tr>\n");
        }
        sb.Append("</table>\n");
        Response.Write(sb.ToString());
        Response.End();
    }