When overridden in a derived class, moves the XPathNavigator object returned by the Current property to the next node in the selected node set.
(in System.Xml.dll)
Visual Basic (Declaration)
Public MustOverride Function MoveNext As Boolean
Dim instance As XPathNodeIterator
Dim returnValue As Boolean
returnValue = instance.MoveNext()
public abstract bool MoveNext()
public:
virtual bool MoveNext() abstract
public abstract function MoveNext() : boolean
The XPathNodeIterator object is positioned on the first node in the selected node set only after the initial call to the MoveNext method. The node set is created in document order. Therefore, calling the MoveNext method moves to the next node in document order.
There are two ways to iterate over an XPathNavigator collection by using the XPathNodeIterator class.
One way is to use MoveNext and then call Current to get the current XPathNavigator instance, as in the following example:
While nodeIterator.MoveNext()
Dim n As XPathNavigator = nodeIterator.Current
Console.WriteLine(n.LocalName)
End While
while (nodeIterator.MoveNext())
{
XPathNavigator n = nodeIterator.Current;
Console.WriteLine(n.LocalName);
}
while (nodeIterator->MoveNext())
{
XPathNavigator^ n = nodeIterator->Current;
Console::WriteLine(n->LocalName);
}
Another way is to use a foreach loop to call GetEnumerator and use the returned IEnumerator interface to enumerate the nodes, as in the following example:
For Each n As XPathNavigator In nodeIterator
Console.WriteLine(nav.LocalName)
Next
foreach (XPathNavigator n in nodeIterator)
Console.WriteLine(n.LocalName);
for each (XPathNavigator^ n in nodeIterator)
Console::WriteLine(n->LocalName);
You should either use MoveNext and Current or use GetEnumerator. Combining these two approaches can cause unexpected results. For example, if the MoveNext is called first, and then GetEnumerator 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.
The following example uses the Select method of the XPathNavigator class to select a node set using the XPathNodeIterator class.
Dim document As XPathDocument = New XPathDocument("books.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()
Dim nodes As XPathNodeIterator = navigator.Select("/bookstore/book")
nodes.MoveNext()
Dim nodesNavigator As XPathNavigator = nodes.Current
Dim nodesText As XPathNodeIterator = nodesNavigator.SelectDescendants(XPathNodeType.Text, False)
While nodesText.MoveNext()
Console.WriteLine(nodesText.Current.Value)
End While
XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();
XPathNodeIterator nodes = navigator.Select("/bookstore/book");
nodes.MoveNext();
XPathNavigator nodesNavigator = nodes.Current;
XPathNodeIterator nodesText = nodesNavigator.SelectDescendants(XPathNodeType.Text, false);
while (nodesText.MoveNext())
Console.WriteLine(nodesText.Current.Value);
XPathDocument^ document = gcnew XPathDocument("books.xml");
XPathNavigator^ navigator = document->CreateNavigator();
XPathNodeIterator^ nodes = navigator->Select("/bookstore/book");
nodes->MoveNext();
XPathNavigator^ nodesNavigator = nodes->Current;
XPathNodeIterator^ nodesText = nodesNavigator->SelectDescendants(XPathNodeType::Text, false);
while (nodesText->MoveNext())
Console::WriteLine(nodesText->Current->Value);
The example takes the books.xml file as input.
<bookstore>
<book genre="autobiography" publicationdate="1981-03-22" ISBN="1-861003-11-0">
<title>The Autobiography of Benjamin Franklin</title>
<author>
<first-name>Benjamin</first-name>
<last-name>Franklin</last-name>
</author>
<price>8.99</price>
</book>
<book genre="novel" publicationdate="1967-11-17" ISBN="0-201-63361-2">
<title>The Confidence Man</title>
<author>
<first-name>Herman</first-name>
<last-name>Melville</last-name>
</author>
<price>11.99</price>
</book>
<book genre="philosophy" publicationdate="1991-02-15" ISBN="1-861001-57-6">
<title>The Gorgias</title>
<author>
<name>Plato</name>
</author>
<price>9.99</price>
</book>
</bookstore>
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
Reference