XmlNode::SelectSingleNode Method (String^)


Selects the first XmlNode that matches the XPath expression.

Namespace:   System.Xml
Assembly:  System.Xml (in System.Xml.dll)

XmlNode^ SelectSingleNode(
	String^ xpath


Type: System::String^

The XPath expression. See XPath Examples.

Return Value

Type: System.Xml::XmlNode^

The first XmlNode that matches the XPath query or null if no matching node is found.

Exception Condition

The XPath expression contains a prefix.

If the XPath expression requires namespace resolution, you must use the SelectSingleNode 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 a selected node. 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:


The following Visual Basic code selects an element that contains single quotes:

book = root.SelectSingleNode("descendant::book[title=""'Emma'""]")

This method is a Microsoft extension to the Document Object Model (DOM).

The following example changes the price of the first Jane Austen book.

#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" );
   XmlNode^ book;
   XmlNode^ root = doc->DocumentElement;
   book = root->SelectSingleNode( "descendant::book[author/last-name='Austen']" );

   //Change the price on the book.
   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>
  <book genre="novel" publicationdate="1992" bk:ISBN="1-861002-30-1">
    <title>The Handmaid's Tale</title>
  <book genre="novel" publicationdate="1991" bk:ISBN="1-861001-57-6">
  <book genre="novel" publicationdate="1982" bk:ISBN="1-861001-45-3">
    <title>Sense and Sensibility</title>

.NET Framework
Available since 1.1
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