Extensions.Descendants<T> Method (IEnumerable<T>, XName)

 

Returns a filtered collection of elements that contains the descendant elements of every element and document 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)

public static IEnumerable<XElement> Descendants<T>(
	this IEnumerable<T> source,
	XName name
)
where T : XContainer

Parameters

source
Type: System.Collections.Generic.IEnumerable<T>

An IEnumerable<T> of XContainer that contains the source collection.

name
Type: System.Xml.Linq.XName

The XName to match.

Return Value

Type: System.Collections.Generic.IEnumerable<XElement>

An IEnumerable<T> of XElement that contains the descendant elements of every element and document 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 XContainer.

Visual Basic users can use the Language-Integrated Axes in Visual Basic (LINQ to XML)2 instead of using 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 descendants of the two elements that have the specified element name.


                XElement xmlTree = XElement.Parse(
@"<Root>
    <Para>
        <t>This is some text </t>
        <b>
            <t>where</t>
        </b>
        <t> all of the text nodes must be concatenated. </t>
    </Para>
    <Para>
        <t>This is a second sentence.</t>
    </Para>
</Root>");

string str =
    (from el in xmlTree.Elements("Para").Descendants("t")
    select (string)el)
    .Aggregate(new StringBuilder(),
        (sb, i) => sb.Append(i),
        sb => sb.ToString());

Console.WriteLine(str);

This example produces the following output:

This is some text where all of the text nodes must be concatenated. This is a second sentence.

The following is the same example, but in this case the XML is in a namespace. For more information, see Working with XML Namespaces.


                XNamespace aw = "http://www.adventure-works.com";
XElement xmlTree = XElement.Parse(
@"<Root xmlns='http://www.adventure-works.com'>
    <Para>
        <t>This is some text </t>
        <b>
            <t>where</t>
        </b>
        <t> all of the text nodes must be concatenated. </t>
    </Para>
    <Para>
        <t>This is a second sentence.</t>
    </Para>
</Root>");

string str =
    (from el in xmlTree.Elements(aw + "Para").Descendants(aw + "t")
     select (string)el)
    .Aggregate(new StringBuilder(),
        (sb, i) => sb.Append(i),
        sb => sb.ToString());

Console.WriteLine(str);

This example produces the following output:

This is some text where all of the text nodes must be concatenated. This is a second sentence.

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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