Extensions.Ancestors<T> Method (IEnumerable<T>, XName)
Returns a filtered collection of elements that contains the ancestors of every node in the source collection. Only elements that have a matching XName are included in the collection.
Assembly: System.Xml.Linq (in System.Xml.Linq.dll)
public static IEnumerable<XElement> Ancestors<T>( this IEnumerable<T> source, XName name ) where T : XNode
Parameters
- source
-
Type:
System.Collections.Generic.IEnumerable<T>
An IEnumerable<T> of XNode 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 that contains the ancestors of every node in the source collection. Only elements that have a matching XName are included in the collection.
Type Parameters
- T
The type of the objects in source, constrained to XNode.
If multiple nodes in the source collection have the same ancestor with a matching XName, the ancestor will be included multiple times in the result collection.
This method uses deferred execution.
The following example retrieves a collection of the great grandchildren elements. It then uses this axis method to retrieve all ancestors of all elements in the collection that match a specified XName.
XElement xmlTree = new XElement("Root",
new XElement("Child1",
new XElement("GrandChild1",
new XElement("GreatGrandChild1", "content")
)
),
new XElement("Child2",
new XElement("GrandChild2",
new XElement("GreatGrandChild2", "content")
)
)
);
IEnumerable<XElement> greatGrandChildren =
from el in xmlTree.Descendants()
where el.Name.LocalName.StartsWith("Great")
select el;
Console.WriteLine("Great Grand Children Elements");
Console.WriteLine("----");
foreach (XElement de in greatGrandChildren)
Console.WriteLine(de.Name);
IEnumerable<XElement> allAncestors =
from el in greatGrandChildren.Ancestors("Child1")
select el;
Console.WriteLine("");
Console.WriteLine("Ancestors");
Console.WriteLine("----");
foreach (XElement de in allAncestors)
Console.WriteLine(de.Name);
This example produces the following output:
Great Grand Children Elements ---- GreatGrandChild1 GreatGrandChild2 Ancestors ---- Child1
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 + "Child1",
new XElement(aw + "GrandChild1",
new XElement(aw + "GreatGrandChild1", "content")
)
),
new XElement(aw + "Child2",
new XElement(aw + "GrandChild2",
new XElement(aw + "GreatGrandChild2", "content")
)
)
);
IEnumerable<XElement> greatGrandChildren =
from el in xmlTree.Descendants()
where el.Name.LocalName.StartsWith("Great")
select el;
Console.WriteLine("Great Grand Children Elements");
Console.WriteLine("----");
foreach (XElement de in greatGrandChildren)
Console.WriteLine(de.Name);
IEnumerable<XElement> allAncestors =
from el in greatGrandChildren.Ancestors(aw + "Child1")
select el;
Console.WriteLine("");
Console.WriteLine("Ancestors");
Console.WriteLine("----");
foreach (XElement de in allAncestors)
Console.WriteLine(de.Name);
This example produces the following output:
Great Grand Children Elements
----
{http://www.adventure-works.com}GreatGrandChild1
{http://www.adventure-works.com}GreatGrandChild2
Ancestors
----
{http://www.adventure-works.com}Child1
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1