如何在Linq to XML语句中循环

How how can I do this:

我怎么能这样做:

XDocument xDocument = new XDocument(new XElement("SqlInstall",
            new XElement("Catalogs",
                    new XElement("Install"),
                    foreach (var item in packagedProduct.Installs)
                    {
                            new XElement("File ")..
                    }

                    ))));
XDocument x