title: Can't Save XDocument in Silverlight
body: <p>I want to save a Xdocument to an xml file , and it seems that silverlight doesn't accept string type for xdoc.save(string str), so I had to put a stream inside of it , the problem is that when I put a filestream I got an error saying that "Attempt to access the method failed" and that a MethodeAccessException was unhandled here is my code :</p>
  
  <pre><code>XDocument MainLBItems = XDocument.Load("SampleData/MainLBItems.xml");            
              MainLBItems.Root.Add(new XElement("Item",
                                              new XElement("Title", this.tb_Title.Text),
                                              new XElement("Dscrp", this.tb_Dscrp.Text),
                                              new XElement("Count", "0")));
              FileStream fs = new FileStream("SampleData/MainLBItems.xml", FileMode.Open, FileAccess.Write);
              MainLBItems.Save(fs);
  </code></pre>