The result of the expression (Boolean, number, string, or node set). This maps to bool, double, string, or System.Xml.XPath.XPathNodeIterator objects respectively.
The following C# code converts the Price/text() node to a number, multiplies it by 10, and returns the resulting value.
Example
nav.Evaluate("Price/text()*10");
The XPath position() and last() functions, unless used as a predicate in a location step, require a reference to a node set in order to be evaluated. In this case, you must use the overload which takes an System.Xml.XPath.XPathNodeIterator as an argument; otherwise, position() and last() return 0.
This method has no effect on the state of the System.Xml.XPath.XPathNavigator.