Linq to Xml - come fare se un elemento non esiste?

[andr3a]

ci riprovo ...

var posts = from item in XFeed.Descendants("item")
            select new
            {
                Title = item.Element("title").Value,
                Description = item.Element("description").Value,
                Published = item.Element("pubDate").Value,
                Url = item.Element("link").Value,
                Enclosure = (item.Element("enclosure") ?? new XElement("enclosure", new XAttribute("url", null))).Attribute("url").Value 
            }; 

oppure:

Enclosure = item.Element("enclosure") ? item.Element("enclosure").Attribute("url").Value : null 

:master: