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

Type Parameters

T

The type of the objects in source, constrained to 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.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<T>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

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>

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5

.NET Compact Framework

Supported in: 3.5

XNA Framework

Supported in: 3.0
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