private XElement Serialize(TreeNode node, ContentFilter filter)
{
XElement elem = new XElement(node.Nodes.Count > 0 ? "group" : "item", new XAttribute("id", node.Name), new XAttribute("name", node.Text));
foreach (TreeNode child in node.Nodes)
{
var f = filter.Add(child.Name);
elem.Add(Serialize(child, filter));
}
return(elem);
}