XPathNavigator | C # in a Nutshell, Second Edition

XPathNavigator

System.Xml.XPath (system.xml.dll)

abstract class

This class is a read-only representation of an XPathDocument based on the IXPathNavigable interface. It provides an easy-to-use data object for quick XPath-based navigation, particularly for XSLT transformations.

An XPathNavigator instance maintains its state with the current node position to provide the proper context for any XPath expression evaluation. Initially, the current node is the root node. The current node is changed by using the Select( ) method or the various MoveTo* methods . If the XPath expression evaluates to a set of nodes, the first node of the set is the current node for the XPathNavigator . All the Select* methods return an XPathNodeIterator object containing the set of nodes returned by the function. Except for plain old Select( ) , the Select* functions do not change the current node of the XPathNavigator they are used on. Any actions on the XPathNodeIterator objects that they return also do not affect the originating object.

The Compile( ) method takes an XPath expression string and encapsulates it into a compiled XPathExpression object. XPathExpression objects are used by Select( ) , Evaluate( ) , and Matches( ) as input to search a node list.

 public abstract class  XPathNavigator  : ICloneable {  // Protected Constructors  protected  XPathNavigator  ( );  // Public Instance Properties  public abstract string  BaseURI  {get; }    public abstract bool  HasAttributes  {get; }    public abstract bool  HasChildren  {get; }    public abstract bool  IsEmptyElement  {get; }    public abstract string  LocalName  {get; }    public abstract string  Name  {get; }    public abstract string  NamespaceURI  {get; }    public abstract XmlNameTable  NameTable  {get; }    public abstract XPathNodeType  NodeType  {get; }    public abstract string  Prefix  {get; }    public abstract string  Value  {get; }    public abstract string  XmlLang  {get; }  // Public Instance Methods  public abstract XPathNavigator  Clone  ( );    public virtual XmlNodeOrder  ComparePosition  (XPathNavigator   nav   );    public virtual XPathExpression  Compile  (string   xpath   );    public virtual object  Evaluate  (string   xpath   );    public virtual object  Evaluate  (XPathExpression   expr   );    public virtual object  Evaluate  (XPathExpression   expr   , XPathNodeIterator   context   );    public abstract string  GetAttribute  (string   localName   , string   namespaceURI   );    public abstract string  GetNamespace  (string   name   );    public virtual bool  IsDescendant  (XPathNavigator   nav   );    public abstract bool  IsSamePosition  (XPathNavigator   other   );    public virtual bool  Matches  (string   xpath   );    public virtual bool  Matches  (XPathExpression   expr   );    public abstract bool  MoveTo  (XPathNavigator   other   );    public abstract bool  MoveToAttribute  (string   localName   , string   namespaceURI   );    public abstract bool  MoveToFirst  ( );    public abstract bool  MoveToFirstAttribute  ( );    public abstract bool  MoveToFirstChild  ( );    public bool  MoveToFirstNamespace  ( );    public abstract bool  MoveToFirstNamespace  (XPathNamespaceScope   namespaceScope   );    public abstract bool  MoveToId  (string   id   );    public abstract bool  MoveToNamespace  (string   name   );    public abstract bool  MoveToNext  ( );    public abstract bool  MoveToNextAttribute  ( );    public bool  MoveToNextNamespace  ( );    public abstract bool  MoveToNextNamespace  (XPathNamespaceScope   namespaceScope   );    public abstract bool  MoveToParent  ( );    public abstract bool  MoveToPrevious  ( );    public abstract void  MoveToRoot  ( );    public virtual XPathNodeIterator  Select  (string   xpath   );    public virtual XPathNodeIterator  Select  (XPathExpression   expr   );    public virtual XPathNodeIterator  SelectAncestors  (string   name   , string   namespaceURI   ,         bool   matchSelf   );    public virtual XPathNodeIterator  SelectAncestors  (XPathNodeType   type   , bool   matchSelf   );    public virtual XPathNodeIterator  SelectChildren  (string   name   , string   namespaceURI   );    public virtual XPathNodeIterator  SelectChildren  (XPathNodeType   type   );    public virtual XPathNodeIterator  SelectDescendants  (string   name   , string   namespaceURI   ,         bool   matchSelf   );    public virtual XPathNodeIterator  SelectDescendants  (XPathNodeType   type   , bool   matchSelf   );    public override string  ToString  ( );  // overrides object  }

Returned By

System.Xml.XmlDataDocument.CreateNavigator( ) , System.Xml.XmlNode.CreateNavigator( ) , IXPathNavigable.CreateNavigator( ) , XPathDocument.CreateNavigator( ) , XPathNodeIterator.Current

Passed To

System.Xml.Xsl.IXsltContextFunction.Invoke( ) , System.Xml.Xsl.XsltContext.PreserveWhitespace( ) , System.Xml.Xsl.XslTransform.{Load( ) , Transform( )}