How to: Find a Single Descendant Using the Descendants Method
You can use the Descendants axis method to quickly write code to find a single uniquely named element. This technique is especially useful when you want to find a particular descendant with a specific name. You could write the code to navigate to the desired element, but it is often faster and easier to write the code using the Descendants axis.
Example
This example uses the First standard query operator.
XElement root = XElement.Parse(@"<Root>
<Child1>
<GrandChild1>GC1 Value</GrandChild1>
</Child1>
<Child2>
<GrandChild2>GC2 Value</GrandChild2>
</Child2>
<Child3>
<GrandChild3>GC3 Value</GrandChild3>
</Child3>
<Child4>
<GrandChild4>GC4 Value</GrandChild4>
</Child4>
</Root>");
string grandChild3 = (string)
(from el in root.Descendants("GrandChild3")
select el).First();
Console.WriteLine(grandChild3);
Dim root As XElement = _
<Root>
<Child1>
<GrandChild1>GC1 Value</GrandChild1>
</Child1>
<Child2>
<GrandChild2>GC2 Value</GrandChild2>
</Child2>
<Child3>
<GrandChild3>GC3 Value</GrandChild3>
</Child3>
<Child4>
<GrandChild4>GC4 Value</GrandChild4>
</Child4>
</Root>
Dim grandChild3 As String = _
(From el In root...<GrandChild3> _
Select el).First()
Console.WriteLine(grandChild3)
This code produces the following output:
GC3 Value
The following example shows the same query for XML that is in a namespace. For more information, see Working with XML Namespaces.
XElement root = XElement.Parse(@"<aw:Root xmlns:aw='https://www.adventure-works.com'>
<aw:Child1>
<aw:GrandChild1>GC1 Value</aw:GrandChild1>
</aw:Child1>
<aw:Child2>
<aw:GrandChild2>GC2 Value</aw:GrandChild2>
</aw:Child2>
<aw:Child3>
<aw:GrandChild3>GC3 Value</aw:GrandChild3>
</aw:Child3>
<aw:Child4>
<aw:GrandChild4>GC4 Value</aw:GrandChild4>
</aw:Child4>
</aw:Root>");
XNamespace aw = "https://www.adventure-works.com";
string grandChild3 = (string)
(from el in root.Descendants(aw + "GrandChild3")
select el).First();
Console.WriteLine(grandChild3);
Imports <xmlns:aw='https://www.adventure-works.com'>
Module Module1
Sub Main()
Dim root As XElement = _
<aw:Root>
<aw:Child1>
<aw:GrandChild1>GC1 Value</aw:GrandChild1>
</aw:Child1>
<aw:Child2>
<aw:GrandChild2>GC2 Value</aw:GrandChild2>
</aw:Child2>
<aw:Child3>
<aw:GrandChild3>GC3 Value</aw:GrandChild3>
</aw:Child3>
<aw:Child4>
<aw:GrandChild4>GC4 Value</aw:GrandChild4>
</aw:Child4>
</aw:Root>
Dim grandChild3 As String = _
(From el In root...<aw:GrandChild3> _
Select el).First()
Console.WriteLine(grandChild3)
End Sub
End Module
This code produces the following output:
GC3 Value