asp.net 生成EXCEL文件

public void ExportResult(DataSet ds)
    {
        HttpContext.Current.Response.AddHeader("content-disposition", "attachment; filename=Order.xls");
        HttpContext.Current.Response.Clear();
        HttpContext.Current.Response.Charset = "";
        HttpContext.Current.Response.ContentType = "application/vnd.ms-excel";
        StringWriter stringWrite = new StringWriter();
        HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);

        DataGrid dg = new DataGrid();
        dg.DataSource = ds.Tables[0];
        dg.DataBind();
        dg.RenderControl(htmlWrite);
        HttpContext.Current.Response.Write(stringWrite.ToString());
        HttpContext.Current.Response.End();
    }