Muokkaa

Jaa

XPathNavigator.SelectSingleNode Method

  • Reference

Definition

Namespace:
System.Xml.XPath
Assembly:
System.Xml.ReaderWriter.dll
Assembly:
System.Xml.XPath.dll
Assembly:
System.Xml.dll
Assembly:
netstandard.dll

Selects a single node in the XPathNavigator.

Overloads

SelectSingleNode(String, IXmlNamespaceResolver)

Selects a single node in the XPathNavigator object using the specified XPath query with the IXmlNamespaceResolver object specified to resolve namespace prefixes.
SelectSingleNode(String)

Selects a single node in the XPathNavigator using the specified XPath query.
SelectSingleNode(XPathExpression)

Selects a single node in the XPathNavigator using the specified XPathExpression object.

SelectSingleNode(String, IXmlNamespaceResolver)

Source:
XPathNavigator.cs
Source:
XPathNavigator.cs
Source:
XPathNavigator.cs

Selects a single node in the XPathNavigator object using the specified XPath query with the IXmlNamespaceResolver object specified to resolve namespace prefixes.

public:
 virtual System::Xml::XPath::XPathNavigator ^ SelectSingleNode(System::String ^ xpath, System::Xml::IXmlNamespaceResolver ^ resolver);
public virtual System.Xml.XPath.XPathNavigator? SelectSingleNode (string xpath, System.Xml.IXmlNamespaceResolver? resolver);
public virtual System.Xml.XPath.XPathNavigator SelectSingleNode (string xpath, System.Xml.IXmlNamespaceResolver resolver);
abstract member SelectSingleNode : string * System.Xml.IXmlNamespaceResolver -> System.Xml.XPath.XPathNavigator
override this.SelectSingleNode : string * System.Xml.IXmlNamespaceResolver -> System.Xml.XPath.XPathNavigator
Public Overridable Function SelectSingleNode (xpath As String, resolver As IXmlNamespaceResolver) As XPathNavigator

Parameters

xpath
String

A String representing an XPath expression.

resolver
IXmlNamespaceResolver

The IXmlNamespaceResolver object used to resolve namespace prefixes in the XPath query.

Returns

XPathNavigator

An XPathNavigator object that contains the first matching node for the XPath query specified; otherwise null if there are no query results.

Exceptions

ArgumentException

An error was encountered in the XPath query or the return type of the XPath expression is not a node.

XPathException

The XPath query is not valid.

Examples

The following example selects a single node from the XPathNavigator object based on the XPath query specified and uses the XmlNamespaceManager object specified to resolve namespace prefixes in the XPath query.

XPathDocument^ document = gcnew XPathDocument("contosoBooks.xml");
XPathNavigator^ navigator = document->CreateNavigator();

XmlNamespaceManager^ manager = gcnew XmlNamespaceManager(navigator->NameTable);
manager->AddNamespace("bk", "http://www.contoso.com/books");

XPathNavigator^ node = navigator->SelectSingleNode("//bk:title", manager);
Console::WriteLine(node->InnerXml);

XPathDocument document = new XPathDocument("contosoBooks.xml");
XPathNavigator navigator = document.CreateNavigator();

XmlNamespaceManager manager = new XmlNamespaceManager(navigator.NameTable);
manager.AddNamespace("bk", "http://www.contoso.com/books");

XPathNavigator node = navigator.SelectSingleNode("//bk:title", manager);
Console.WriteLine(node.InnerXml);

Dim document As XPathDocument = New XPathDocument("contosoBooks.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()

Dim manager As XmlNamespaceManager = New XmlNamespaceManager(navigator.NameTable)
manager.AddNamespace("bk", "http://www.contoso.com/books")

Dim node As XPathNavigator = navigator.SelectSingleNode("//bk:title", manager)
Console.WriteLine(node.InnerXml)

The example takes the contosoBooks.xml file as an input.

<?xml version="1.0" encoding="utf-8" ?>  
<bookstore xmlns="http://www.contoso.com/books">  
    <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>

Remarks

The SelectSingleNode method selects the first node that matches the XPath query specified. The SelectSingleNode method uses the IXmlNamespaceResolver object to resolve namespace prefixes.

Note

In XPath all namespaces must be prefixed in a query. If an XML document uses a default namespace, you must still add a namespace prefix to the IXmlNamespaceResolver object.

Applies to

SelectSingleNode(String)

Source:
XPathNavigator.cs
Source:
XPathNavigator.cs
Source:
XPathNavigator.cs

Selects a single node in the XPathNavigator using the specified XPath query.

public:
 virtual System::Xml::XPath::XPathNavigator ^ SelectSingleNode(System::String ^ xpath);
public virtual System.Xml.XPath.XPathNavigator? SelectSingleNode (string xpath);
public virtual System.Xml.XPath.XPathNavigator SelectSingleNode (string xpath);
abstract member SelectSingleNode : string -> System.Xml.XPath.XPathNavigator
override this.SelectSingleNode : string -> System.Xml.XPath.XPathNavigator
Public Overridable Function SelectSingleNode (xpath As String) As XPathNavigator

Parameters

xpath
String

A String representing an XPath expression.

Returns

XPathNavigator

An XPathNavigator object that contains the first matching node for the XPath query specified; otherwise, null if there are no query results.

Exceptions

ArgumentException

An error was encountered in the XPath query or the return type of the XPath expression is not a node.

XPathException

The XPath query is not valid.

Examples

The following example selects a single node from the XPathNavigator based on the XPath query specified.

XPathDocument^ document = gcnew XPathDocument("books.xml");
XPathNavigator^ navigator = document->CreateNavigator();

XPathNavigator^ node = navigator->SelectSingleNode("//title");
Console::WriteLine(node->InnerXml);

XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();

XPathNavigator node = navigator.SelectSingleNode("//title");
Console.WriteLine(node.InnerXml);

Dim document As XPathDocument = New XPathDocument("books.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()

Dim node As XPathNavigator = navigator.SelectSingleNode("//title")
Console.WriteLine(node.InnerXml)

The example takes the books.xml file as an input.

<?xml version="1.0" encoding="utf-8" ?>   
<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>

Remarks

The SelectSingleNode method selects the first node that matches the XPath query in the XPathNavigator object.

Applies to

SelectSingleNode(XPathExpression)

Source:
XPathNavigator.cs
Source:
XPathNavigator.cs
Source:
XPathNavigator.cs

Selects a single node in the XPathNavigator using the specified XPathExpression object.

public:
 virtual System::Xml::XPath::XPathNavigator ^ SelectSingleNode(System::Xml::XPath::XPathExpression ^ expression);
public virtual System.Xml.XPath.XPathNavigator? SelectSingleNode (System.Xml.XPath.XPathExpression expression);
public virtual System.Xml.XPath.XPathNavigator SelectSingleNode (System.Xml.XPath.XPathExpression expression);
abstract member SelectSingleNode : System.Xml.XPath.XPathExpression -> System.Xml.XPath.XPathNavigator
override this.SelectSingleNode : System.Xml.XPath.XPathExpression -> System.Xml.XPath.XPathNavigator
Public Overridable Function SelectSingleNode (expression As XPathExpression) As XPathNavigator

Parameters

expression
XPathExpression

An XPathExpression object containing the compiled XPath query.

Returns

XPathNavigator

An XPathNavigator object that contains the first matching node for the XPath query specified; otherwise null if there are no query results.

Exceptions

ArgumentException

An error was encountered in the XPath query or the return type of the XPath expression is not a node.

XPathException

The XPath query is not valid.

Examples

The following example selects a single node from the XPathNavigator based on the XPath query contained in the XPathExpression.

XPathDocument^ document = gcnew XPathDocument("books.xml");
XPathNavigator^ navigator = document->CreateNavigator();

XPathExpression^ query = navigator->Compile("//title");

XPathNavigator^ node = navigator->SelectSingleNode(query);
Console::WriteLine(node->InnerXml);

XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();

XPathExpression query = navigator.Compile("//title");

XPathNavigator node = navigator.SelectSingleNode(query);
Console.WriteLine(node.InnerXml);

Dim document As XPathDocument = New XPathDocument("books.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()

Dim query As XPathExpression = navigator.Compile("//title")

Dim node As XPathNavigator = navigator.SelectSingleNode(query)
Console.WriteLine(node.InnerXml)

The example takes the books.xml file as an input.

<?xml version="1.0" encoding="utf-8" ?>   
<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>

Remarks

The SelectSingleNode method selects the first node that matches the compiled XPath query contained in the XPathExpression object in the XPathNavigator.

Applies to