public class XPathDocument : IXPathNavigable {
// Public Constructors
   public XPathDocument( System.IO.Stream stream);  
   public XPathDocument( string uri);  
   public XPathDocument( string uri, System.Xml.XmlSpace space);  
   public XPathDocument( System.IO.TextReader reader);  
   public XPathDocument( System.Xml.XmlReader reader);  
   public XPathDocument( System.Xml.XmlReader reader, System.Xml.XmlSpace space);  
// Public Instance Methods
   public XPathNavigator CreateNavigator( );                           // implements IXPathNavigable
}

This class is a concrete implementation of IXPathNavigable for creating an XPathNavigator that knows how to scan through an XML document. There are overloaded forms of the constructor designed to pull an XML document from various sources—a System.IO.Stream, a string, a System.IO.TextReader (which presumably is pulling from some other valid data source), or a System.Xml.XmlReader. Note that if the XmlReader is currently positioned on top of a particular node within a document, the constructed XPathDocument instance is only valid for that element and its children. This allows partial XPath scans of a given document.

This class serves no other purpose than as a factory for producing XPathNavigator instances.