Extensions.XPathSelectElements Method (XNode, String, IXmlNamespaceResolver)
Selects a collection of elements using an XPath expression, resolving namespace prefixes using the specified IXmlNamespaceResolver.
Namespace: System.Xml.XPath
Assembly: System.Xml.Linq (in System.Xml.Linq.dll)
'Declaration <ExtensionAttribute> _ Public Shared Function XPathSelectElements ( _ node As XNode, _ expression As String, _ resolver As IXmlNamespaceResolver _ ) As IEnumerable(Of XElement)
Parameters
- node
- Type: System.Xml.Linq.XNode
The XNode on which to evaluate the XPath expression.
- expression
- Type: System.String
A String that contains an XPath expression.
- resolver
- Type: System.Xml.IXmlNamespaceResolver
A IXmlNamespaceResolver for the namespace prefixes in the XPath expression.
Return Value
Type: System.Collections.Generic.IEnumerable(Of XElement)An IEnumerable(Of T) of XElement that contains the selected elements.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type XNode. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).You can use this method to evaluate XPath expressions that contain namespace prefixes.
Although the ordering of returned collections is not specified in the XML XPath Language 1.0 Recommendation, this extension method returns nodes in document order.
Note that nodes are returned in document order even when you use a reverse axis, such as preceding-sibling or ancestor-or-self.
This example creates an XML tree that contains a namespace. It uses an XmlReader to read the XML document. It then gets an XmlNameTable from the XmlReader, and an XmlNamespaceManager from the XmlNameTable. It uses the XmlNamespaceManager when selecting the list of elements.
Dim markup As XElement = _ <aw:Root xmlns:aw="http://www.adventure-works.com"> <aw:Child1>child one data 1</aw:Child1> <aw:Child1>child one data 2</aw:Child1> <aw:Child1>child one data 3</aw:Child1> <aw:Child2>child two data 4</aw:Child2> <aw:Child2>child two data 5</aw:Child2> <aw:Child2>child two data 6</aw:Child2> </aw:Root> Dim reader As XmlReader = markup.CreateReader Dim nameTable As XmlNameTable = reader.NameTable Dim namespaceManager As XmlNamespaceManager = New XmlNamespaceManager(nameTable) namespaceManager.AddNamespace("aw", "http://www.adventure-works.com") Dim elements As IEnumerable(Of XElement) = markup.XPathSelectElements("./aw:Child1", namespaceManager) For Each el As XElement In elements Console.WriteLine(el) Next
This example produces the following output:
<aw:Child1 xmlns:aw="http://www.adventure-works.com">child one data 1</aw:Child1> <aw:Child1 xmlns:aw="http://www.adventure-works.com">child one data 2</aw:Child1> <aw:Child1 xmlns:aw="http://www.adventure-works.com">child one data 3</aw:Child1>
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
