create XML File and display on the Browser

Hi I need to create Xml file Dynamically and i have to display on the browser,
But here before display on the browser i have to save and open option like ( when we click download button in mails it will show to us save option and open option)

i tried like this
string strvalue = "<?xml version='1.0' encoding='UTF-8'?> <gallery> <image> <thumbnail>images/small/                     image01.jpg</thumbnail> </image> </gallery>";
        XmlDocument xDoc = new XmlDocument();
        xDoc.LoadXml(strvalue);
        xDoc.Save(Server.MapPath(".") + "//XMLFile.xml");
        Response.Clear();
      ...