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XmlComment.SelectSingleNode Method

Selects the first XmlNode that matches the XPath expression.

This member is overloaded. For complete information about this member, including syntax, usage, and examples, click a name in the overload list.

  Name Description
Public method SelectSingleNode(String) Selects the first XmlNode that matches the XPath expression. (Inherited from XmlNode.)
Public method SelectSingleNode(String, XmlNamespaceManager) Selects the first XmlNode that matches the XPath expression. Any prefixes found in the XPath expression are resolved using the supplied XmlNamespaceManager. (Inherited from XmlNode.)
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XPath expressions can include namespaces. Namespace resolution is supported using the XmlNamespaceManager. If the XPath expression includes a prefix, the prefix and namespace URI pair must be added to the XmlNamespaceManager.

Note Note

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 add a prefix and namespace URI to the XmlNamespaceManager; otherwise, you will not get any nodes selected. For more information, see Select Nodes Using XPath Navigation.

The following example returns the first book with the matching author name. The XmlNamespaceManager resolves the default namespace in the XPath expression.

using System;
using System.IO;
using System.Xml;

public class Sample
{
  public static void Main()
  {

      XmlDocument doc = new XmlDocument();
      doc.Load("newbooks.xml");

      // Create an XmlNamespaceManager to resolve the default namespace.
      XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
      nsmgr.AddNamespace("bk", "urn:newbooks-schema");

      // Select the first book written by an author whose last name is Atwood.
      XmlNode book;
      XmlElement root = doc.DocumentElement;
     book = root.SelectSingleNode("descendant::bk:book[bk:author/bk:last-name='Atwood']", nsmgr);

      Console.WriteLine(book.OuterXml);

  }
}

The example uses the file, newbooks.xml, as input.

<?xml version='1.0'?>
<bookstore xmlns="urn:newbooks-schema">
  <book genre="novel" style="hardcover">
    <title>The Handmaid's Tale</title>
    <author>
      <first-name>Margaret</first-name>
      <last-name>Atwood</last-name>
    </author>
    <price>19.95</price>
  </book>
  <book genre="novel" style="other">
    <title>The Poisonwood Bible</title>
    <author>
      <first-name>Barbara</first-name>
      <last-name>Kingsolver</last-name>
    </author>
    <price>11.99</price>
  </book>
</bookstore>
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