Language

Extensions.Descendants Method

Definition

Namespace:
System.Xml.Linq
Assemblies:
System.Xml.Linq.dll, System.Xml.XDocument.dll
Assemblies:
netstandard.dll, System.Xml.XDocument.dll
Assembly:
System.Xml.XDocument.dll
Assembly:
System.Xml.Linq.dll
Assembly:
netstandard.dll

Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

Overloads

Name Description
Descendants(IEnumerable, XName)

Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.
Descendants(IEnumerable)

Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

Remarks

Visual Basic users can use the integrated XML descendant axis to retrieve the descendant elements of a collection. However, the integrated axis only retrieves descendants with a specified name. If Visual Basic users want to retrieve all descendants, then they must use this axis method explicitly.

This method uses deferred execution.

Descendants(IEnumerable, XName)

Source:
Extensions.cs
Source:
Extensions.cs
Source:
Extensions.cs
Source:
Extensions.cs
Source:
Extensions.cs

Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.

public:
generic 
 where T : System::Xml::Linq::XContainer[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable ^ Descendants(System::Collections::Generic::IEnumerable ^ source, System::Xml::Linq::XName ^ name);
public static System.Collections.Generic.IEnumerable Descendants(this System.Collections.Generic.IEnumerable source, System.Xml.Linq.XName name) where T : System.Xml.Linq.XContainer;
public static System.Collections.Generic.IEnumerable Descendants(this System.Collections.Generic.IEnumerable source, System.Xml.Linq.XName? name) where T : System.Xml.Linq.XContainer;
static member Descendants : seq<'T (requires 'T :> System.Xml.Linq.XContainer)> * System.Xml.Linq.XName -> seq (requires 'T :> System.Xml.Linq.XContainer)

Public Function Descendants(Of T As XContainer) (source As IEnumerable(Of T), name As XName) As IEnumerable(Of XElement)

Type Parameters

T

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

Parameters

source
IEnumerable

An IEnumerable of XContainer that contains the source collection.

name
XName

The XName to match.

Returns

IEnumerable<XElement>

An IEnumerable of XElement that contains the descendant elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.

Examples

The following example retrieves a collection of two elements, and then retrieves a collection of all descendants of the two elements that have the specified element name.

XElement xmlTree = XElement.Parse(
@"
    
        This is some text 
        
            where
        
         all of the text nodes must be concatenated. 
    
    
        This is a second sentence.
    
");

string str =
    (from el in xmlTree.Elements("Para").Descendants("t")
    select (string)el)
    .Aggregate(new StringBuilder(),
        (sb, i) => sb.Append(i),
        sb => sb.ToString());

Console.WriteLine(str);

Dim xmlTree As XElement = _
    
        
            This is some text 
            
                where
            
             all of the text nodes must be concatenated. 
        
        
            This is a second sentence.
        
    

Dim str As String = _
    ( _
        From el In xmlTree.... _
        Select CStr(el) _
    ) _
    .Aggregate(New StringBuilder(), _
               Function(ByVal sb, ByVal i) sb.Append(i), _
               Function(ByVal sb) sb.ToString())

Console.WriteLine(str)

This example produces the following output:

This is some text where all of the text nodes must be concatenated. This is a second sentence.

The following is the same example, but in this case the XML is in a namespace. For more information, see Work with XML Namespaces.

XNamespace aw = "http://www.adventure-works.com";
XElement xmlTree = XElement.Parse(
@"
    
        This is some text 
        
            where
        
         all of the text nodes must be concatenated. 
    
    
        This is a second sentence.
    
");

string str =
    (from el in xmlTree.Elements(aw + "Para").Descendants(aw + "t")
     select (string)el)
    .Aggregate(new StringBuilder(),
        (sb, i) => sb.Append(i),
        sb => sb.ToString());

Console.WriteLine(str);

Imports 

Module Module1
    Sub Main()
        Dim xmlTree As XElement = _
            
                
                    This is some text 
                    
                        where
                    
                     all of the text nodes must be concatenated. 
                
                
                    This is a second sentence.
                
            

        Dim str As String = _
            ( _
                From el In xmlTree.... _
                Select CStr(el) _
            ) _
            .Aggregate(New StringBuilder(), _
                       Function(sb, i) sb.Append(i), _
                       Function(sb) sb.ToString())

        Console.WriteLine(str)
    End Sub
End Module

This example produces the following output:

This is some text where all of the text nodes must be concatenated. This is a second sentence.

Remarks

Visual Basic users can use the Language-Integrated Axes in Visual Basic (LINQ to XML) instead of using this axis method explicitly.

This method uses deferred execution.

See also

Applies to

Descendants(IEnumerable)

Source:
Extensions.cs
Source:
Extensions.cs
Source:
Extensions.cs
Source:
Extensions.cs
Source:
Extensions.cs

Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

public:
generic 
 where T : System::Xml::Linq::XContainer[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable ^ Descendants(System::Collections::Generic::IEnumerable ^ source);
public static System.Collections.Generic.IEnumerable Descendants(this System.Collections.Generic.IEnumerable source) where T : System.Xml.Linq.XContainer;
public static System.Collections.Generic.IEnumerable Descendants(this System.Collections.Generic.IEnumerable source) where T : System.Xml.Linq.XContainer;
static member Descendants : seq<'T (requires 'T :> System.Xml.Linq.XContainer)> -> seq (requires 'T :> System.Xml.Linq.XContainer)

Public Function Descendants(Of T As XContainer) (source As IEnumerable(Of T)) As IEnumerable(Of XElement)

Type Parameters

T

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

Parameters

source
IEnumerable

An IEnumerable of XContainer that contains the source collection.

Returns

IEnumerable<XElement>

An IEnumerable of XElement that contains the descendant elements of every element and document in the source collection.

Examples

The following example retrieves a collection of elements, and then uses this axis method to retrieve all descendent elements of every item in the collection of elements.

XElement xmlTree = XElement.Parse(
@"
    
        This is some text 
        
            where
        
         all of the nodes must be concatenated. 
    
    
        This is a second sentence.
    
");

IEnumerable elList =
    from el in xmlTree.Elements("Para").Descendants()
    select el;

foreach (XElement el in elList)
    Console.WriteLine(el);

Dim xmlTree As XElement = _
    
        
            This is some text 
            
                where
            
             all of the nodes must be concatenated. 
        

        
            This is a second sentence.
        
    

Dim elList = From el In xmlTree..Descendants _
                        Select el

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

This example produces the following output:

This is some text 

  where

where
 all of the nodes must be concatenated. 
This is a second sentence.

The following is the same example, but in this case the XML is in a namespace. For more information, see Work with XML Namespaces.

XNamespace aw = "http://www.adventure-works.com";
XElement xmlTree = XElement.Parse(
@"
    
        This is some text 
        
            where
        
         all of the nodes must be concatenated. 
    
    
        This is a second sentence.
    
");

IEnumerable elList =
    from el in xmlTree.Elements(aw + "Para").Descendants()
    select el;

foreach (XElement el in elList)
    Console.WriteLine(el);

Imports 

Module Module1
    Sub Main()
        Dim xmlTree As XElement = _
            
                
                    This is some text 
                    
                        where
                    
                     all of the nodes must be concatenated. 
                

                
                    This is a second sentence.
                
            

        Dim elList = From el In xmlTree..Descendants _
                                Select el

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

This example produces the following output:

This is some text 

  where

where
 all of the nodes must be concatenated. 
This is a second sentence.

Remarks

Visual Basic users can use the integrated XML descendant axis to retrieve the descendant elements of a collection. However, the integrated axis only retrieves descendants with a specified name. If Visual Basic users want to retrieve all descendants, then they must use this axis method explicitly.

This method uses deferred execution.

See also

Applies to