Xdoc1 and Xdoc2 are the XML's you want to compare and nodesnotfound gives you the list of nodes from xdoc1 not found in xdoc2.
I just wrote few lines quickly…test it properly.
List<string> nodesnotFound = new List<string>();
bool nodefound = false;
foreach (XmlNode xnode1 in xdoc1)
{
foreach (XmlNode xnode2 in xdoc2)
{
if (xnode1.Name == xnode2.Name)
nodefound = true;
}
if (!nodefound)
{
nodesnotFound.Add(xnode1.Name);
}
nodefound = false;
}