title: Creating objects from xml error {"Value cannot be null.\r\nParameter name: element"}
body: <p>I need to create a list of objects parsing an XML document.
  Issue appears when projecting to <code>AdvertisementFullScreen</code></p>
  
  <p>I receive this error:</p>
  
  <pre><code>{"Value cannot be null.\r\nParameter name: element"}
  </code></pre>
  
  <p>My code:</p>
  
  <pre><code>var advFs = loadedData.Element("xxx")
                             .Elements("advertisementsFullScreen")
                             .Elements("advertisement") // RESULT BELOW
                             .Select(x=&gt;new AdvertisementFullScreen()
                             {
                                 Id = (int)x.Element("id"),
                                 ImageUrl = (string)x.Element("imageUrl"),
                                 DisplayTime = new TimeSpan(0, 0, (int)x.Element("displayTime"))
                             }).ToList();
  </code></pre>
  
  <p>Result before projecting is:</p>
  
  <pre><code>[0] = &lt;advertisement id="7001" imageUrl="C:/xxx/Test-data/data-offline/Assets/advertisementsFullScreen/1.png" displayTime="5" isSelfPromo="1"&gt;&lt;/advertisement&gt;
  </code></pre>