Extensions.DescendantNodes(Of T) Method (IEnumerable(Of T))
Returns a collection of the descendant nodes of every document and element in the source collection.
Assembly: System.Xml.Linq (in System.Xml.Linq.dll)
<ExtensionAttribute> Public Shared Function DescendantNodes(Of T As XContainer) ( source As IEnumerable(Of T) ) As IEnumerable(Of XNode)
Parameters
- source
-
Type:
System.Collections.Generic.IEnumerable(Of T)
An IEnumerable(Of T) of XContainer that contains the source collection.
Return Value
Type: System.Collections.Generic.IEnumerable(Of XNode)An IEnumerable(Of T) of XNode of the descendant nodes of every document and element in the source collection.
Type Parameters
- T
The type of the objects in source, constrained to XContainer.
This axis extension method is used on XDocument and XElement objects. Both of these types derive from XContainer, so this method operates on an IEnumerable(Of T) of XContainer that contains the source collection.
Although Visual Basic has an integrated XML axis for descendant elements, there is no integrated axis for descendant nodes, so Visual Basic users must use this axis method explicitly.
This method uses deferred execution.
The following example retrieves a collection of two elements, and then retrieves a collection of all descendant nodes for every element in the source collection. Note that the attribute of the GrandChild element is not surfaced as a node.
Dim xmlTree As XElement = _
<Root>
<Child>aaa<GrandChild anAttribute='xyz'>Text</GrandChild>
<!--a comment-->
<?xml-stylesheet type='text/xsl' href='test.xsl'?>
</Child>
<Child>ccc<GrandChild>Text</GrandChild>ddd</Child>
</Root>
Dim nodes As IEnumerable(Of XNode) = _
From node In xmlTree.<Child>.DescendantNodes _
Select node
For Each node As XNode In nodes
Select Case node.NodeType
Case XmlNodeType.Element
Console.WriteLine("Element: {0}", DirectCast(node, XElement).Name)
Case XmlNodeType.Text
Console.WriteLine("Text: {0}", DirectCast(node, XText).Value)
Case XmlNodeType.Comment
Console.WriteLine("Comment: {0}", DirectCast(node, XComment).Value)
Case XmlNodeType.ProcessingInstruction
Console.WriteLine("PI: {0}", DirectCast(node, XProcessingInstruction).Data)
End Select
Next
This example produces the following output:
Text: aaa Element: GrandChild Text: Text Comment: a comment PI: type='text/xsl' href='test.xsl' Text: ccc Element: GrandChild Text: Text Text: ddd
The following is the same example, but in this case the XML is in a namespace. For more information, see Working with XML Namespaces.
Imports <xmlns="http://www.adventure-works.com">
Module Module1
Sub Main()
Dim xmlTree As XElement = _
<Root>
<Child>aaa<GrandChild anAttribute='xyz'>Text</GrandChild>
<!--a comment-->
<?xml-stylesheet type='text/xsl' href='test.xsl'?>
</Child>
<Child>ccc<GrandChild>Text</GrandChild>ddd</Child>
</Root>
Dim nodes As IEnumerable(Of XNode) = _
From node In xmlTree.<Child>.DescendantNodes _
Select node
For Each node As XNode In nodes
Select Case node.NodeType
Case XmlNodeType.Element
Console.WriteLine("Element: {0}", DirectCast(node, XElement).Name)
Case XmlNodeType.Text
Console.WriteLine("Text: {0}", DirectCast(node, XText).Value)
Case XmlNodeType.Comment
Console.WriteLine("Comment: {0}", DirectCast(node, XComment).Value)
Case XmlNodeType.ProcessingInstruction
Console.WriteLine("PI: {0}", DirectCast(node, XProcessingInstruction).Data)
End Select
Next
End Sub
End Module
This example produces the following output:
Text: aaa
Element: {http://www.adventure-works.com}GrandChild
Text: Text
Comment: a comment
PI: type='text/xsl' href='test.xsl'
Text: ccc
Element: {http://www.adventure-works.com}GrandChild
Text: Text
Text: ddd
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1