XmlDocument.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.
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SelectSingleNode(String) | Selects the first XmlNode that matches the XPath expression. (Inherited from XmlNode.) |
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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.) |
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
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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>
