Extensions.DescendantNodes(IEnumerable<T>) Extensions.DescendantNodes(IEnumerable<T>) Extensions.DescendantNodes(IEnumerable<T>) Extensions.DescendantNodes(IEnumerable<T>) Method

Definição

Namespace:: System.Xml.Linq System.Xml.Linq System.Xml.Linq System.Xml.Linq

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

Retorna uma coleção dos nós descendentes de todos os documentos e elementos na coleção de origem.Returns a collection of the descendant nodes of every document and element in the source collection.

public:
generic <typename T>
 where T : System::Xml::Linq::XContainer[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable<System::Xml::Linq::XNode ^> ^ DescendantNodes(System::Collections::Generic::IEnumerable<T> ^ source);

public static System.Collections.Generic.IEnumerable<System.Xml.Linq.XNode> DescendantNodes<T> (this System.Collections.Generic.IEnumerable<T> source) where T : System.Xml.Linq.XContainer;

static member DescendantNodes : seq<'T (requires 'T :> System.Xml.Linq.XContainer)> -> seq<System.Xml.Linq.XNode> (requires 'T :> System.Xml.Linq.XContainer)

<Extension()>
Public Function DescendantNodes(Of T As XContainer) (source As IEnumerable(Of T)) As IEnumerable(Of XNode)

Parâmetros de tipo

T

O tipo dos objetos em source, restritos para XContainer.The type of the objects in source, constrained to XContainer.

Parâmetros

source: IEnumerable<T> IEnumerable<T> IEnumerable<T> IEnumerable<T>

Um IEnumerable<T> do XContainer que contém a coleção de origem.An IEnumerable<T> of XContainer that contains the source collection.

Retornos

IEnumerable<XNode>

Um IEnumerable<T> de XNode dos nós descendentes de todos os documentos e elementos na coleção de origem.An IEnumerable<T> of XNode of the descendant nodes of every document and element in the source collection.

Exemplos

O exemplo a seguir recupera uma coleção de dois elementos e, em seguida, recupera uma coleção de todos os nós descendentes para cada elemento na coleção de origem.The following example retrieves a collection of two elements, and then retrieves a collection of all descendant nodes for every element in the source collection. Observe que o atributo do GrandChild elemento não está na superfície como um nó.Note that the attribute of the GrandChild element is not surfaced as a node.

XElement xmlTree = XElement.Parse(  
@"<Root>  
    <Child>aaa<GrandChild anAttribute='xyz'>Text</GrandChild>  
        <!--a comment-->  
        <?xml-stylesheet type='text/xsl' href='test.xsl'?>  
    </Child>  
    <Child>ccc<GrandChild>Text</GrandChild>ddd</Child>  
</Root>");  
IEnumerable<XNode> nodes =  
    from node in xmlTree.Elements("Child").DescendantNodes()  
    select node;  
  
foreach (XNode node in nodes)  
{  
    switch (node.NodeType)  
    {  
        case XmlNodeType.Element:  
            Console.WriteLine("Element: {0}", ((XElement)node).Name);  
            break;  
        case XmlNodeType.Text:  
            Console.WriteLine("Text: {0}", ((XText)node).Value);  
            break;  
        case XmlNodeType.Comment:  
            Console.WriteLine("Comment: {0}", ((XComment)node).Value);  
            break;  
        case XmlNodeType.ProcessingInstruction:  
            Console.WriteLine("PI: {0}", ((XProcessingInstruction)node).Data);  
            break;  
    }  
}

Dim xmlTree As XElement = _  
<Root>  
    <Child>aaa<GrandChild anAttribute='xyz'>Text</GrandChild>  
        <!--a comment-->  
        <?xml-stylesheet type='text/xsl' href='test.xsl'?>  
    </Child>  
    <Child>ccc<GrandChild>Text</GrandChild>ddd</Child>  
</Root>  
  
Dim nodes As IEnumerable(Of XNode) = _  
    From node In xmlTree.<Child>.DescendantNodes _  
    Select node  
  
For Each node As XNode In nodes  
    Select Case node.NodeType  
        Case XmlNodeType.Element  
            Console.WriteLine("Element: {0}", DirectCast(node, XElement).Name)  
        Case XmlNodeType.Text  
            Console.WriteLine("Text: {0}", DirectCast(node, XText).Value)  
        Case XmlNodeType.Comment  
            Console.WriteLine("Comment: {0}", DirectCast(node, XComment).Value)  
        Case XmlNodeType.ProcessingInstruction  
            Console.WriteLine("PI: {0}", DirectCast(node, XProcessingInstruction).Data)  
    End Select  
Next

Este exemplo gera a seguinte saída:This example produces the following output:

Text: aaa  
Element: GrandChild  
Text: Text  
Comment: a comment  
PI: type='text/xsl' href='test.xsl'  
Text: ccc  
Element: GrandChild  
Text: Text  
Text: ddd

O exemplo a seguir é o mesmo, mas, nesse caso, o XML está em um namespace.The following is the same example, but in this case the XML is in a namespace. Para obter mais informações, consulte trabalhando com namespaces XML.For more information, see Working with XML Namespaces.

XNamespace aw = "http://www.adventure-works.com";  
XElement xmlTree = XElement.Parse(  
@"<Root xmlns='http://www.adventure-works.com'>  
    <Child>aaa<GrandChild anAttribute='xyz'>Text</GrandChild>  
        <!--a comment-->  
        <?xml-stylesheet type='text/xsl' href='test.xsl'?>  
    </Child>  
    <Child>ccc<GrandChild>Text</GrandChild>ddd</Child>  
</Root>");  
IEnumerable<XNode> nodes =  
    from node in xmlTree.Elements(aw + "Child").DescendantNodes()  
    select node;  
  
foreach (XNode node in nodes)  
{  
    switch (node.NodeType)  
    {  
        case XmlNodeType.Element:  
            Console.WriteLine("Element: {0}", ((XElement)node).Name);  
            break;  
        case XmlNodeType.Text:  
            Console.WriteLine("Text: {0}", ((XText)node).Value);  
            break;  
        case XmlNodeType.Comment:  
            Console.WriteLine("Comment: {0}", ((XComment)node).Value);  
            break;  
        case XmlNodeType.ProcessingInstruction:  
            Console.WriteLine("PI: {0}", ((XProcessingInstruction)node).Data);  
            break;  
    }  
}

Imports <xmlns="http://www.adventure-works.com">  
  
Module Module1  
    Sub Main()  
        Dim xmlTree As XElement = _  
        <Root>  
            <Child>aaa<GrandChild anAttribute='xyz'>Text</GrandChild>  
                <!--a comment-->  
                <?xml-stylesheet type='text/xsl' href='test.xsl'?>  
            </Child>  
            <Child>ccc<GrandChild>Text</GrandChild>ddd</Child>  
        </Root>  
  
        Dim nodes As IEnumerable(Of XNode) = _  
            From node In xmlTree.<Child>.DescendantNodes _  
            Select node  
  
        For Each node As XNode In nodes  
            Select Case node.NodeType  
                Case XmlNodeType.Element  
                    Console.WriteLine("Element: {0}", DirectCast(node, XElement).Name)  
                Case XmlNodeType.Text  
                    Console.WriteLine("Text: {0}", DirectCast(node, XText).Value)  
                Case XmlNodeType.Comment  
                    Console.WriteLine("Comment: {0}", DirectCast(node, XComment).Value)  
                Case XmlNodeType.ProcessingInstruction  
                    Console.WriteLine("PI: {0}", DirectCast(node, XProcessingInstruction).Data)  
            End Select  
        Next  
    End Sub  
End Module

Este exemplo gera a seguinte saída:This example produces the following output:

Text: aaa  
Element: {http://www.adventure-works.com}GrandChild  
Text: Text  
Comment: a comment  
PI: type='text/xsl' href='test.xsl'  
Text: ccc  
Element: {http://www.adventure-works.com}GrandChild  
Text: Text  
Text: ddd

Comentários

Esse método de extensão de eixo é XDocument usado XElement nos objetos e.This axis extension method is used on XDocument and XElement objects. Esses dois tipos derivam de XContainer, portanto, esse método opera em IEnumerable<T> um XContainer de que contém a coleção de origem.Both of these types derive from XContainer, so this method operates on an IEnumerable<T> of XContainer that contains the source collection.

Embora Visual Basic tenha um eixo XML integrado para elementos descendentes, não há nenhum eixo integrado para nós descendentes, de modo que Visual Basic os usuários devem usar explicitamente esse método de eixo.Although Visual Basic has an integrated XML axis for descendant elements, there is no integrated axis for descendant nodes, so Visual Basic users must use this axis method explicitly.

Este método utiliza execução adiada.This method uses deferred execution.