XPathNodeIterator XPathNodeIterator XPathNodeIterator XPathNodeIterator Class


Provides an iterator over a selected set of nodes.

public ref class XPathNodeIterator abstract : ICloneable, System::Collections::IEnumerable
public abstract class XPathNodeIterator : ICloneable, System.Collections.IEnumerable
type XPathNodeIterator = class
    interface ICloneable
    interface IEnumerable
Public MustInherit Class XPathNodeIterator
Implements ICloneable, IEnumerable


The following example uses the Select method of the XPathNavigator class to select a node set using the XPathNodeIterator class.

XPathDocument^ document = gcnew XPathDocument("books.xml");
XPathNavigator^ navigator = document->CreateNavigator();

XPathNodeIterator^ nodes = navigator->Select("/bookstore/book");
XPathNavigator^ nodesNavigator = nodes->Current;

XPathNodeIterator^ nodesText = nodesNavigator->SelectDescendants(XPathNodeType::Text, false);

while (nodesText->MoveNext())
XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();

XPathNodeIterator nodes = navigator.Select("/bookstore/book");
XPathNavigator nodesNavigator = nodes.Current;

XPathNodeIterator nodesText = nodesNavigator.SelectDescendants(XPathNodeType.Text, false);

while (nodesText.MoveNext())
Dim document As XPathDocument = New XPathDocument("books.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()

Dim nodes As XPathNodeIterator = navigator.Select("/bookstore/book")
Dim nodesNavigator As XPathNavigator = nodes.Current

Dim nodesText As XPathNodeIterator = nodesNavigator.SelectDescendants(XPathNodeType.Text, False)

While nodesText.MoveNext()
End While

The example takes the books.xml file as input.

<?xml version="1.0" encoding="utf-8" ?>   
    <book genre="autobiography" publicationdate="1981-03-22" ISBN="1-861003-11-0">  
        <title>The Autobiography of Benjamin Franklin</title>  
    <book genre="novel" publicationdate="1967-11-17" ISBN="0-201-63361-2">  
        <title>The Confidence Man</title>  
    <book genre="philosophy" publicationdate="1991-02-15" ISBN="1-861001-57-6">  
        <title>The Gorgias</title>  


An XPathNodeIterator object returned by the XPathNavigator class is not positioned on the first node in a selected set of nodes. A call to the MoveNext method of the XPathNodeIterator class must be made to position the XPathNodeIterator object on the first node in the selected set of nodes.

When using the XPathNodeIterator, if you edit the current node or any of its ancestors, your current position is lost. If you want to edit a number of nodes that you have selected, create a XPathNavigator array, copy all of the nodes from the XPathNodeIterator into the array, then iterate through the array and modify the nodes.

There are two ways to iterate over an XPathNavigator collection by using the XPathNodeIterator class.

One way is to use the MoveNext method and then call Current to get the current XPathNavigator instance, as in the following example:

while (nodeIterator->MoveNext())
    XPathNavigator^ n = nodeIterator->Current;
while (nodeIterator.MoveNext())
    XPathNavigator n = nodeIterator.Current;
While nodeIterator.MoveNext()
    Dim n As XPathNavigator = nodeIterator.Current
End While

Another way is to use a foreach loop to call the GetEnumerator method and use the returned IEnumerator interface to enumerate the nodes, as in the following example:

for each (XPathNavigator^ n in nodeIterator)
foreach (XPathNavigator n in nodeIterator)
For Each n As XPathNavigator In nodeIterator

You should either use MoveNext and Current or use GetEnumerator. Combining these two approaches can cause unexpected results. For example, if the MoveNext method is called first, and then the GetEnumerator method is called in the foreach loop, the foreach loop will not start enumerating the results from the beginning of the collection, but from the position after the Current method.

Notes to Inheritors

When you inherit from the XPathNodeIterator class, you must override the following members:


XPathNodeIterator() XPathNodeIterator() XPathNodeIterator() XPathNodeIterator()

Initializes a new instance of the XPathNodeIterator class.


Count Count Count Count

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

Current Current Current Current

When overridden in a derived class, gets the XPathNavigator object for this XPathNodeIterator, positioned on the current context node.

CurrentPosition CurrentPosition CurrentPosition CurrentPosition

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


Clone() Clone() Clone() Clone()

When overridden in a derived class, returns a clone of this XPathNodeIterator object.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetEnumerator() GetEnumerator() GetEnumerator() GetEnumerator()

Returns an IEnumerator object to iterate through the selected node set.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
MoveNext() MoveNext() MoveNext() MoveNext()

When overridden in a derived class, moves the XPathNavigator object returned by the Current property to the next node in the selected node set.

ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)

Explicit Interface Implementations

ICloneable.Clone() ICloneable.Clone() ICloneable.Clone() ICloneable.Clone()

Creates a new object that is a copy of the current instance.

Extension Methods

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

Enables parallelization of a query.

AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

Converts an IEnumerable to an IQueryable.

Applies to