XDocument xml = new XDocument(
                new XElement("Parent",
                    new XElement("Child1","Child1 Data"),
                    new XElement("Child2","Child2 Data")
                    )
                );
            string result = (from x in xml.Elements("Parent").Elements()
                         where x.Value == "Child1 Data"
                         select x.Value).First();
            Console.WriteLine(result);