Artikel
11/18/2011

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

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

Returns a filtered collection of the attributes 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 Attributes ( _
    source As IEnumerable(Of XElement), _
    name As XName _
) As IEnumerable(Of XAttribute)

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

Parameters

source
Type: System.Collections.Generic.IEnumerable<XElement>
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<XAttribute>
An IEnumerable<T> of XAttribute that contains a filtered collection of the attributes 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

Note that unlike some other XML programming interfaces, in LINQ to XML, namespaces are surfaced as attributes.

This method uses deferred execution.

Examples

The following example retrieves a collection of elements, which in this case includes the Child1 and Child2 elements. It then retrieves all attributes of that child collection with a name of Att1.

Dim output As New StringBuilder
Dim xmlTree As XElement = _
    <Root Att1="content1" Att2="content2">
        <Child1 Att1="content3" Att2="content4">
        </Child1>
        <Child2 Att1="content5" Att2="content6">
        </Child2>
    </Root>

Dim attList = From att In xmlTree.Elements.Attributes("Att1") _
                          Select att

For Each att As XAttribute In attList
    output.Append(att)
    output.Append(Environment.NewLine)
Next


OutputTextBlock.Text = output.ToString()

StringBuilder output = new StringBuilder();
XElement xmlTree = new XElement("Root",
    new XAttribute("Att1", "content1"),
    new XAttribute("Att2", "content2"),
    new XElement("Child1",
        new XAttribute("Att1", "content3"),
        new XAttribute("Att2", "content4")
    ),
    new XElement("Child2",
        new XAttribute("Att1", "content5"),
        new XAttribute("Att2", "content6")
    )
);

IEnumerable<XAttribute> attList = from att in xmlTree.Elements().Attributes("Att1")
                                  select att;

foreach (XAttribute att in attList)
    output.Append(att + 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.

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