Extensions.Ancestors(Of T) Method (IEnumerable(Of T), XName)
Returns a filtered collection of elements that contains the ancestors of every node in the source collection. Only elements that have a matching XName are included in the collection.
Assembly: System.Xml.Linq (in System.Xml.Linq.dll)
<ExtensionAttribute> Public Shared Function Ancestors(Of T As XNode) ( source As IEnumerable(Of T), name As XName ) As IEnumerable(Of XElement)
Parameters
- source
-
Type:
System.Collections.Generic.IEnumerable(Of T)
An IEnumerable(Of T) of XNode that contains the source collection.
- name
-
Type:
System.Xml.Linq.XName
The XName to match.
Return Value
Type: System.Collections.Generic.IEnumerable(Of XElement)An IEnumerable(Of T) of XElement that contains the ancestors of every node in the source collection. Only elements that have a matching XName are included in the collection.
Type Parameters
- T
The type of the objects in source, constrained to XNode.
If multiple nodes in the source collection have the same ancestor with a matching XName, the ancestor will be included multiple times in the result collection.
This method uses deferred execution.
The following example retrieves a collection of the great grandchildren elements. It then uses this axis method to retrieve all ancestors of all elements in the collection that match a specified XName.
Dim xmlTree As XElement = _
<Root>
<Child1>
<GrandChild1>
<GreatGrandChild1>content</GreatGrandChild1>
</GrandChild1>
</Child1>
<Child2>
<GrandChild2>
<GreatGrandChild2>content</GreatGrandChild2>
</GrandChild2>
</Child2>
</Root>
Dim greatGrandChildren = From el In xmlTree.Descendants _
Where el.Name.LocalName.StartsWith("Great") _
Select el
Console.WriteLine("Great Grand Children Elements")
Console.WriteLine("----")
For Each de As XElement In greatGrandChildren
Console.WriteLine(de.Name)
Next
Dim allAncestors = From el In greatGrandChildren.Ancestors("Child1") _
Select el
Console.WriteLine("")
Console.WriteLine("Ancestors")
Console.WriteLine("----")
For Each de As XElement In allAncestors
Console.WriteLine(de.Name)
Next
This example produces the following output:
Great Grand Children Elements ---- GreatGrandChild1 GreatGrandChild2 Ancestors ---- Child1
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>
<Child1>
<GrandChild1>
<GreatGrandChild1>content</GreatGrandChild1>
</GrandChild1>
</Child1>
<Child2>
<GrandChild2>
<GreatGrandChild2>content</GreatGrandChild2>
</GrandChild2>
</Child2>
</Root>
Dim greatGrandChildren = From el In xmlTree.Descendants _
Where el.Name.LocalName.StartsWith("Great") _
Select el
Console.WriteLine("Great Grand Children Elements")
Console.WriteLine("----")
For Each de As XElement In greatGrandChildren
Console.WriteLine(de.Name)
Next
Dim allAncestors = From el In greatGrandChildren.Ancestors(GetXmlNamespace() + "Child1") _
Select el
Console.WriteLine("")
Console.WriteLine("Ancestors")
Console.WriteLine("----")
For Each de As XElement In allAncestors
Console.WriteLine(de.Name)
Next
End Sub
End Module
This example produces the following output:
Great Grand Children Elements
----
{http://www.adventure-works.com}GreatGrandChild1
{http://www.adventure-works.com}GreatGrandChild2
Ancestors
----
{http://www.adventure-works.com}Child1
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