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How to retrieve a single attribute (LINQ to XML)

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This article explains how to retrieve a single attribute of an element, given the attribute name. This is useful for writing query expressions where you want to find an element that has a particular attribute.

The Attribute method of the XElement class returns the XAttribute with the specified name.

Example: Retrieve attribute values, given the element and attribute names

The following example uses the XElement method to create an element named PhoneNumbers. It then finds all the descendant elements named Phone and, for each, uses the Attribute method to obtain and output the value of the attribute named type:

XElement cust = new XElement("PhoneNumbers",
    new XElement("Phone",
        new XAttribute("type", "home"),
        "555-555-5555"),
    new XElement("Phone",
        new XAttribute("type", "work"),
        "555-555-6666")
);
IEnumerable<XElement> elList =
    from el in cust.Descendants("Phone")
    select el;
foreach (XElement el in elList)
    Console.WriteLine((string)el.Attribute("type"));

Dim cust As XElement = <PhoneNumbers>
                           <Phone type="home">555-555-5555</Phone>
                           <Phone type="work">555-555-6666</Phone>
                       </PhoneNumbers>
Dim elList = From el In cust...<Phone>
For Each e As XElement In elList
    Console.WriteLine(e.@type)
Next

This example produces the following output:

home
work

Example: Retrieve an attribute value with a cast

You can retrieve the value of an attribute by casting it, just as you do for with XElement objects. The following example demonstrates this:

XElement cust = new XElement("PhoneNumbers",
    new XElement("Phone",
        new XAttribute("type", "home"),
        "555-555-5555"),
    new XElement("Phone",
        new XAttribute("type", "work"),
        "555-555-6666")
);
IEnumerable<XElement> elList =
    from el in cust.Descendants("Phone")
    select el;
foreach (XElement el in elList)
    Console.WriteLine((string)el.Attribute("type"));

Dim cust As XElement = <PhoneNumbers>
                           <Phone type="home">555-555-5555</Phone>
                           <Phone type="work">555-555-6666</Phone>
                       </PhoneNumbers>
Dim elList As IEnumerable(Of XElement) = _
    From el In cust...<Phone> _
    Select el
For Each el As XElement In elList
    Console.WriteLine(el.@type)
Next

This example produces the following output:

home
work

LINQ to XML provides explicit cast operators for the XAttribute class to string, bool, bool?, int, int?, uint, uint?, long, long?, ulong, ulong?, float, float?, double, double?, decimal, decimal?, DateTime, DateTime?, TimeSpan, TimeSpan?, GUID, and GUID?.

Example: Cast for an attribute in a namespace

The following example shows the same code for an attribute that's in a namespace. For more information, see Namespaces overview.

XNamespace aw = "http://www.adventure-works.com";
XElement cust = new XElement(aw + "PhoneNumbers",
    new XElement(aw + "Phone",
        new XAttribute(aw + "type", "home"),
        "555-555-5555"),
    new XElement(aw + "Phone",
        new XAttribute(aw + "type", "work"),
        "555-555-6666")
);
IEnumerable<XElement> elList =
    from el in cust.Descendants(aw + "Phone")
    select el;
foreach (XElement el in elList)
    Console.WriteLine((string)el.Attribute(aw + "type"));

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

Module Module1
    Sub Main()
        Dim cust As XElement = _
            <aw:PhoneNumbers>
                <aw:Phone aw:type="home">555-555-5555</aw:Phone>
                <aw:Phone aw:type="work">555-555-6666</aw:Phone>
            </aw:PhoneNumbers>
        Dim elList As IEnumerable(Of XElement) = _
            From el In cust...<aw:Phone> _
            Select el
        For Each el As XElement In elList
            Console.WriteLine(el.@aw:type)
        Next
    End Sub
End Module

This example produces the following output:

home
work

See also