static void Main(string[] args)
{
XmlDocument doc = new XmlDocument();
Node root = new Node();
string input =
"<root>" +
"<node id=\"1\">" +
"<nodeName>node1</nodeName>" +
"<node id=\"2\">" +
"<nodeName>node2</nodeName>" +
"<node id=\"21\">" +
"<nodeName>node21</nodeName>" +
"</node>" +
"<node id=\"22\">" +
"<nodeName>node22</nodeName>" +
"</node>" +
"</node>" +
"<node id=\"3\">" +
"<nodeName>node3</nodeName>" +
"<node id=\"31\">" +
"<nodeName>node31</nodeName>" +
"</node>" +
"</node>" +
"<node id=\"4\">" +
"<nodeName>node4</nodeName>" +
"<node id=\"41\">" +
"<nodeName>node41</nodeName>" +
"</node>" +
"</node>" +
"</node>" +
"</root>";
XElement element = XElement.Parse(input);
doc = new XmlDocument();
doc.LoadXml(element.ToString());
XmlNode node = (XmlNode)doc;
root.AddNode(node, root);
}
