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

 

Returns a filtered collection of the child 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> Elements<T>(
	this IEnumerable<T> source,
	XName name
)
where T : XContainer

Parameters

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

An IEnumerable<T> of XElement 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 of the child 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 integrated elements axis to retrieve the child elements of every element in a collection.

This method uses deferred execution.

This extension method is useful when you want to retrieve all elements with a specified name at a particular depth. This is easy if the document is very regular, but if the document is irregular, it can be a bit more difficult. In the following example, we want to retrieve all aaa elements that are children of Item elements. A given Item element may or may not contain an aaa element. This is easily accomplished using this extension method, as follows:


                XElement xmlTree = new XElement("Root",
    new XElement("Item",
        new XElement("aaa", 1),
        new XElement("bbb", 2)
    ),
    new XElement("Item",
        new XElement("ccc", 3),
        new XElement("aaa", 4)
    ),
    new XElement("Item",
        new XElement("ddd", 5),
        new XElement("eee", 6)
    )
);

IEnumerable<XElement> allGrandChildren =
    from el in xmlTree.Elements("Item").Elements("aaa")
    select el;

foreach (XElement el in allGrandChildren)
    Console.WriteLine(el);

This example produces the following output:

<aaa>1</aaa>
<aaa>4</aaa>

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 = new XElement(aw + "Root",
    new XElement(aw + "Item",
        new XElement(aw + "aaa", 1),
        new XElement(aw + "bbb", 2)
    ),
    new XElement(aw + "Item",
        new XElement(aw + "ccc", 3),
        new XElement(aw + "aaa", 4)
    ),
    new XElement(aw + "Item",
        new XElement(aw + "ddd", 5),
        new XElement(aw + "eee", 6)
    )
);

IEnumerable<XElement> allGrandChildren =
    from el in xmlTree.Elements(aw + "Item").Elements(aw + "aaa")
    select el;

foreach (XElement el in allGrandChildren)
    Console.WriteLine(el);

This example produces the following output:

<aaa xmlns="http://www.adventure-works.com">1</aaa>
<aaa xmlns="http://www.adventure-works.com">4</aaa>

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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