Save XDocument issue - silverlight-4.0

Question

I'm loading my document like so:
WebClient client = new WebClient();
client.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted);
client.OpenReadAsync(new Uri("Rolls.xml", UriKind.Relative));
Then on the Read Completed:
XDocument doc = XDocument.Load(XmlReader.Create(e.Result));
using (Stream stream = e.Result)
{
{
foreach (var roll in _rollsToAddStudentTo)
{
doc.Element("rolls").Add(new XElement("rollid", roll));
}
doc.Save(stream);
}
}
The problem is when it gets to the save I get the error
"Specified method is not supported."
Help will be much appreciated.
Cheers
Thanks Jehof,
So, how would I incorporate my document into that async method?
foreach (var roll in _rollsToAddStudentTo)
{
doc.Element("rolls").Add(new XElement("rollid", roll));
}
WebClient client = new WebClient();
client.OpenWriteCompleted += new OpenWriteCompletedEventHandler(client_OpenWriteCompleted);
client.OpenWriteAsync(new Uri("Rolls.xml", UriKind.Relative));
I have resolved this by changing my logic to below.
using (IsolatedStorageFile isoStore =
IsolatedStorageFile.GetUserStoreForApplication())
{
// Create new file
using (IsolatedStorageFileStream isoStream =
new IsolatedStorageFileStream("Rolls.xml",
FileMode.Create, isoStore))
{
// Write to the Isolated Storage for the user.
XmlWriterSettings settings = new XmlWriterSettings();
settings.Indent = true;
// Create an XmlWriter.
using (XmlWriter writer = XmlWriter.Create(isoStream, settings))
{
writer.WriteStartDocument();
writer.WriteStartElement("Rolls");
foreach (var roll in _rollsToAddStudentTo)
{
writer.WriteStartElement("roll");
writer.WriteAttributeString("rollid", roll);
writer.WriteEndElement();
}
writer.WriteEndElement();
writer.WriteEndDocument();
}
}
}

Answer 1

The stream you try to save the XDocument is readonly. Cause it is the stream you get passed as argument to your method client_OpenReadCompleted that is registered to the event OpenReadCompleted.
If you want to save your XDocument back via WebClient you need to call one of the OpenWriteAsync-methods.