Selects a list of nodes matching the XPath expression.
Public Function SelectNodes ( _ xpath As String _ ) As XmlNodeList
Dim instance As XmlNode Dim xpath As String Dim returnValue As XmlNodeList returnValue = instance.SelectNodes(xpath)
public XmlNodeList SelectNodes( string xpath )
public: XmlNodeList^ SelectNodes( String^ xpath )
public function SelectNodes( xpath : String ) : XmlNodeList
The XPath expression contains a prefix.
If the XPath expression requires namespace resolution, you must use the SelectNodes overload which takes an XmlNamespaceManager as its argument. The XmlNamespaceManager is used to resolve namespaces.
If the XPath expression does not include a prefix, it is assumed that the namespace URI is the empty namespace. If your XML includes a default namespace, you must still use the XmlNamespaceManager and add a prefix and namespace URI to it; otherwise, you will not get any nodes selected. For more information, see Select Nodes Using XPath Navigation.
A common issue when formulating XPath expressions is how to include a single quote (') or double quote (") in the expression. If you have to search for a value that includes a single quote, you must enclose the string in double quotes. If you need to search for a value that includes a double quote, you must enclose the string in single quotes.
For example, suppose you have the following XML:
<bookstore> <book> <title>'Emma'</title> </book> </bookstore>
The following Visual Basic code selects an element that contains single quotes:
nodeList = root.SelectNodes("//book[contains(title,""'Emma'"")]")
This method is a Microsoft extension to the Document Object Model (DOM).
The following example changes the price on all books by Jane Austen.
Imports System Imports System.IO Imports System.Xml public class Sample public shared sub Main() 'Create the XmlDocument. Dim doc as XmlDocument = new XmlDocument() doc.Load("booksort.xml") Dim book as XmlNode Dim nodeList as XmlNodeList Dim root as XmlNode = doc.DocumentElement nodeList=root.SelectNodes("descendant::book[author/last-name='Austen']") 'Change the price on the books. for each book in nodeList book.LastChild.InnerText="15.95" next Console.WriteLine("Display the modified XML document....") doc.Save(Console.Out) end sub end class
using System; using System.IO; using System.Xml; public class Sample { public static void Main() { XmlDocument doc = new XmlDocument(); doc.Load("booksort.xml"); XmlNodeList nodeList; XmlNode root = doc.DocumentElement; nodeList=root.SelectNodes("descendant::book[author/last-name='Austen']"); //Change the price on the books. foreach (XmlNode book in nodeList) { book.LastChild.InnerText="15.95"; } Console.WriteLine("Display the modified XML document...."); doc.Save(Console.Out); } }
#using <System.Xml.dll> using namespace System; using namespace System::IO; using namespace System::Xml; int main() { XmlDocument^ doc = gcnew XmlDocument; doc->Load( "booksort.xml" ); XmlNodeList^ nodeList; XmlNode^ root = doc->DocumentElement; nodeList = root->SelectNodes( "descendant::book[author/last-name='Austen']" ); //Change the price on the books. System::Collections::IEnumerator^ myEnum = nodeList->GetEnumerator(); while ( myEnum->MoveNext() ) { XmlNode^ book = safe_cast<XmlNode^>(myEnum->Current); book->LastChild->InnerText = "15.95"; } Console::WriteLine( "Display the modified XML document...." ); doc->Save( Console::Out ); }
The example uses the file, booksort.xml, as input.
<?xml version="1.0"?> <!-- A fragment of a book store inventory database --> <bookstore xmlns:bk="urn:samples"> <book genre="novel" publicationdate="1997" bk:ISBN="1-861001-57-8"> <title>Pride And Prejudice</title> <author> <first-name>Jane</first-name> <last-name>Austen</last-name> </author> <price>24.95</price> </book> <book genre="novel" publicationdate="1992" bk:ISBN="1-861002-30-1"> <title>The Handmaid's Tale</title> <author> <first-name>Margaret</first-name> <last-name>Atwood</last-name> </author> <price>29.95</price> </book> <book genre="novel" publicationdate="1991" bk:ISBN="1-861001-57-6"> <title>Emma</title> <author> <first-name>Jane</first-name> <last-name>Austen</last-name> </author> <price>19.95</price> </book> <book genre="novel" publicationdate="1982" bk:ISBN="1-861001-45-3"> <title>Sense and Sensibility</title> <author> <first-name>Jane</first-name> <last-name>Austen</last-name> </author> <price>19.95</price> </book> </bookstore>
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Select Nodes Using XPath Navigation: http://msdn.microsoft.com/en-us/library/d271ytdx.aspxXPath Reference: http://msdn.microsoft.com/en-us/library/ms256115.aspx