• Article

Extensions.AncestorsAndSelf Method (IEnumerable<XElement>, XName)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Returns a filtered collection of elements that contains every element in the source collection, and the ancestors of every element in the source collection. Only elements that have a matching XName are included in the collection.

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

Syntax

'Declaration
<ExtensionAttribute> _
Public Shared Function AncestorsAndSelf ( _
    source As IEnumerable(Of XElement), _
    name As XName _
) As IEnumerable(Of XElement)

public static IEnumerable<XElement> AncestorsAndSelf(
    this IEnumerable<XElement> source,
    XName name
)

Parameters

Return Value

Type: System.Collections.Generic.IEnumerable<XElement>
An IEnumerable<T> of XElement that contains every element in the source collection, and the ancestors of every element in the source collection. Only elements that have a matching XName are included in the collection.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<XElement>. When you use instance method syntax to call this method, omit the first parameter.

Exceptions

Exception Condition
ArgumentNullException

source is nulla null reference (Nothing in Visual Basic).

Remarks

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.

Examples

The following example retrieves a collection of the great grandchildren elements. It then uses this axis method to retrieve all self and ancestors of all elements in the collection that match a specified XName.

Dim output As New StringBuilder
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

output.Append("Great Grand Children Elements")
output.Append(Environment.NewLine)
output.Append("----")
output.Append(Environment.NewLine)

For Each de As XElement In greatGrandChildren
    output.Append(de.Name)
    output.Append(Environment.NewLine)
Next

Dim allAncestors = From el In greatGrandChildren.AncestorsAndSelf("GreatGrandChild1") _
                   Select el

output.Append("")
output.Append(Environment.NewLine)
output.Append("Ancestors and Self")
output.Append(Environment.NewLine)
output.Append("----")
output.Append(Environment.NewLine)

For Each de As XElement In allAncestors
    output.Append(de.Name)
    output.Append(Environment.NewLine)
Next


OutputTextBlock.Text = output.ToString()

StringBuilder output = new StringBuilder();
XElement xmlTree = new XElement("Root",
    new XElement("Child1",
        new XElement("GrandChild1",
            new XElement("GreatGrandChild1", "content")
        )
    ),
    new XElement("Child2",
        new XElement("GrandChild2",
            new XElement("GreatGrandChild2", "content")
        )
    )
);
IEnumerable<XElement> greatGrandChildren =
    from el in xmlTree.Descendants()
    where el.Name.LocalName.StartsWith("Great")
    select el;

output.Append("Great Grand Children Elements" + Environment.NewLine);
output.Append("----" + Environment.NewLine);
foreach (XElement de in greatGrandChildren)
    output.Append(de.Name + Environment.NewLine);

IEnumerable<XElement> allAncestors =
    from el in greatGrandChildren.AncestorsAndSelf("GreatGrandChild1")
    select el;

output.Append("" + Environment.NewLine);
output.Append("Ancestors and Self" + Environment.NewLine);
output.Append("----" + Environment.NewLine);
foreach (XElement de in allAncestors)
    output.Append(de.Name + Environment.NewLine);

OutputTextBlock.Text = output.ToString();

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.