asp.net c# ต้องการให้เขียนลง textfile แล้วดาวโหลดออกมาโดยให้ถามที่จัดเก็บก่อน

        System.Web.HttpResponse response = System.Web.HttpContext.Current.Response;
        response.ClearContent();
        response.Clear();
        response.ContentType = "text/plain";
        response.AddHeader("Content-Disposition", 
                           "attachment; filename=" + fileName + ";");
        response.TransmitFile(Server.MapPath("text.txt"));
        response.Flush();    
        response.End();

Dim response As System.Web.HttpResponse = System.Web.HttpContext.Current.Response
response.ClearContent()
response.Clear()
response.ContentType = "text/plain"
response.AddHeader("Content-Disposition", "attachment; filename=" + fileName + ";")
response.TransmitFile(Server.MapPath("text.txt"))
response.Flush()
response.End()