A string that contains the value of the namespace node; string.Empty if a matching namespace node is not found, or if the System.Xml.XPath.XPathNavigator is not positioned on an element node.
Namespaces xml and xmlns always return a value. If string.Empty is specified as the name parameter, the XPathNavigator.GetNamespace(string) method returns the default xmlns namespace.
For a definition of namespace nodes, see section 5.4 of the W3C XML Path Language (XPath) recommendation located at http://www.w3.org/TR/xpath#data-model.
This method does not affect the state of the System.Xml.XPath.XPathNavigator.