System.Xml.XPath.XPathNodeIterator Class

Summary

Provides an iterator over a set of selected nodes.

C# Syntax:

public abstract class XPathNodeIterator : ICloneable

System.Xml.XPath Namespace

System.Xml.XPath.XPathNodeIterator Member List:

Public Properties

Count	Read-only Gets the index of the last node in the selected set of nodes.
Current	Read-only When overridden in a derived class, returns the navigator for this XPathNodeIterator positioned on the current node.
CurrentPosition	Read-only When overridden in a derived class, gets the index of the current position in the selected set of nodes.

Public Methods

Clone	When overridden in a derived class, creates a new XPathNodeIterator.
Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetHashCode (inherited from System.Object)	See base class member description: System.Object.GetHashCode Derived from System.Object, the primary base class for all objects.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
MoveNext	When overridden in a derived class, moves the XPathNavigator to the next node in the selected set.
ToString (inherited from System.Object)	See base class member description: System.Object.ToString Derived from System.Object, the primary base class for all objects.

Protected Constructors

ctor #1

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

Protected Methods

Finalize (inherited from System.Object)	See base class member description: System.Object.Finalize Derived from System.Object, the primary base class for all objects.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Hierarchy:

• System.Object
• System.Xml.XPath.XPathNodeIterator

System.Xml.XPath.XPathNodeIterator Member Details

Summary:

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

C# Syntax:

protected XPathNodeIterator();

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Summary

Gets the index of the last node in the selected set of nodes.

C# Syntax:

public virtual int Count {get;}

The Count property clones the XPathNodeIterator and walks the node set. As a result, there can be some performance loss depending on the number of items in the node set.

The Count property does not effect the current position of the XPathNodeIterator.

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Summary

When overridden in a derived class, returns the navigator for this XPathNodeIterator positioned on the current node.

C# Syntax:

public abstract XPathNavigator Current {get;}

You can use the properties of the XPathNavigator to return information on the current node. However, the XPathNavigator cannot be used to move away from the selected node set. Doing so could invalidate the state of the navigator. Alternatively, you can clone the XPathNavigator. The cloned XPathNavigator can then be moved away from the selected node set. This is an application level decision. Providing this functionality may effect the performance of the XPath query.

Although in the majority of cases the same XPathNavigator is returned for all nodes in the selected node set, this is not guaranteed. In the following example, the resultant node set is a combination of the nodes from the loaded document, "Myfile.xml", and "bar.xml" which was loaded by the XPath engine into an XPathDocument object. Because these are two different data stores ( XmlDocument and XPathDocument), the IXPathNavigable.CreateNavigator method hands out different implementations of the XPathNavigator. Hence, the typeof call will indicate different implementations of the XPathNavigator.Note: This could also occur when passing an XPathNodeIterator to an <msxsl:script> function.

              XPathDocument Doc = new XPathDocument("Myfile.xml");
              XPathNavigator Nav =  Doc.CreateNavigator();
              XPathNodeIterator Iterator = Nav.Select("child::* | document(/"bar.xml/")");
              while (Iterator.MoveNext())
                Console.WriteLine(typeof(Iterator.Current));
            

If the XPathNavigator.SelectAncestors, XPathNavigator.SelectDescendants and XPathNavigator.SelectChildren methods result in no nodes being selected it is not guaranteed that Current is pointing to the context node.

See XPathExpression.AddSort (in the XPathExpression class) for an example using this property.

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Summary

When overridden in a derived class, gets the index of the current position in the selected set of nodes.

C# Syntax:

public abstract int CurrentPosition {get;}

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Summary

When overridden in a derived class, creates a new XPathNodeIterator.

C# Syntax:

public abstract XPathNodeIterator Clone();

Return Value:

A new XPathNodeIterator object.

The cloned XPathNodeIterator is not effected by subsequent changes to the current XPathNodeIterator.

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Inherited
See base class member description: System.Object.Equals

C# Syntax:

public virtual bool Equals(    object obj );

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.Finalize

C# Syntax:

~XPathNodeIterator();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.GetHashCode

C# Syntax:

public virtual int GetHashCode();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.GetType

C# Syntax:

public Type GetType();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.MemberwiseClone

C# Syntax:

protected object MemberwiseClone();

For more information on members inherited from System.Object click on the link above.

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Summary

When overridden in a derived class, moves the XPathNavigator to the next node in the selected set.

C# Syntax:

public abstract bool MoveNext();

Return Value:

true if the XPathNavigator moved to the next node; false if there are no more selected nodes.

The node set is created in document order, therefore calling this method moves to the next node in document order. The XPathNodeIterator is positioned on the first node in the selected set after the initial call to MoveNext. This makes it easy to write a while loop.

              XPathDocument doc = new XPathDocument("data.xml");
              XPathNavigator nav = doc.CreateNavigator();
              XPathNodeIterator iterator = nav.Select("/bookstore/book[3]");
              while (iterator.MoveNext()){
                Console.WriteLine(iterator.Current.Name);
              }
                 
            

See XPathExpression.SetContext (in the XPathExpression class) for an example using this method.

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Inherited
See base class member description: System.Object.ToString

C# Syntax:

public virtual string ToString();

For more information on members inherited from System.Object click on the link above.

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