Extensions.AncestorsAndSelf Method (IEnumerable(Of XElement))

 
System_CAPS_noteNote

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Returns a collection of elements that contains every element in the source collection, and the ancestors of every element in the source collection.

Namespace:   System.Xml.Linq
Assembly:  System.Xml.Linq (in System.Xml.Linq.dll)

<ExtensionAttribute>
Public Shared Function AncestorsAndSelf (
	source As IEnumerable(Of XElement)
) As IEnumerable(Of XElement)

Parameters

source
Type: System.Collections.Generic.IEnumerable(Of XElement)

An IEnumerable(Of T) of XElement that contains the source collection.

Return Value

Type: System.Collections.Generic.IEnumerable(Of XElement)

An IEnumerable(Of T) of XElement that contains every element in the source collection, and the ancestors of every element in the source collection.

If multiple nodes in the source collection have the same ancestor, the ancestor will be included multiple times in the result collection. To avoid this, use the Distinct method.

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 and self of all elements in the collection.


                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.AncestorsAndSelf.Distinct _
                   Select el

Console.WriteLine("")
Console.WriteLine("Ancestors and Self")
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 and Self
----
GreatGrandChild1
GrandChild1
Child1
Root
GreatGrandChild2
GrandChild2
Child2

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.AncestorsAndSelf.Distinct _
                           Select el

        Console.WriteLine("")
        Console.WriteLine("Ancestors and Self")
        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 and Self
----
{http://www.adventure-works.com}GreatGrandChild1
{http://www.adventure-works.com}GrandChild1
{http://www.adventure-works.com}Child1
{http://www.adventure-works.com}Root
{http://www.adventure-works.com}GreatGrandChild2
{http://www.adventure-works.com}GrandChild2
{http://www.adventure-works.com}Child2

Universal Windows Platform
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
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