Extensions.Elements(T) Method (IEnumerable(T), XName) (System.Xml.Linq)

.NET Framework Class Library

Extensions..::.Elements<(Of <(T>)>) Method (IEnumerable<(Of <(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)

Syntax

Visual Basic (Declaration)

<ExtensionAttribute> _
Public Shared Function Elements(Of T As XContainer) ( _
    source As IEnumerable(Of T), _
    name As XName _
) As IEnumerable(Of XElement)

Visual Basic (Usage)

Dim source As IEnumerable(Of T)
Dim name As XName
Dim returnValue As IEnumerable(Of XElement)

returnValue = source.Elements(name)

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

Visual C++

[ExtensionAttribute]
public:
generic<typename T>
where T : XContainer
static IEnumerable<XElement^>^ Elements(
    IEnumerable<T>^ source, 
    XName^ name
)

JScript

JScript does not support generic types or methods.

Type Parameters

T: The type of the objects in source, constrained to XContainer.

Parameters

source: Type: System.Collections.Generic..::.IEnumerable<(Of <(T>)>)
An IEnumerable<(Of <(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<(Of <(XElement>)>)
An IEnumerable<(Of <(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<(Of <(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).

Remarks

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.

Examples

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);

Visual Basic

Dim xmlTree As XElement = _
    <Root>
        <Item>
            <aaa>1</aaa>
            <bbb>2</bbb>
        </Item>

        <Item>
            <ccc>3</ccc>
            <aaa>4</aaa>
        </Item>

        <Item>
            <ddd>5</ddd>
            <eee>6</eee>
        </Item>
    </Root>

Dim allGrandChildren = From el In xmlTree.<Item>.<aaa> _
                       Select el

For Each el As XElement In allGrandChildren
    Console.WriteLine(el)
Next

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);

Visual Basic

Imports <xmlns="http://www.adventure-works.com">

Module Module1
    Sub Main()
        Dim xmlTree As XElement = _
            <Root>
                <Item>
                    <aaa>1</aaa>
                    <bbb>2</bbb>
                </Item>

                <Item>
                    <ccc>3</ccc>
                    <aaa>4</aaa>
                </Item>

                <Item>
                    <ddd>5</ddd>
                    <eee>6</eee>
                </Item>
            </Root>

        Dim allGrandChildren = From el In xmlTree.<Item>.<aaa> _
                               Select el

        For Each el As XElement In allGrandChildren
            Console.WriteLine(el)
        Next
    End Sub
End Module

This example produces the following output:

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

Platforms

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.

Version Information