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

定義

命名空間:: System.Xml.Linq

組件:: System.Xml.Linq.dll, System.Xml.XDocument.dll

組件:: netstandard.dll, System.Xml.XDocument.dll

組件:: System.Xml.XDocument.dll

組件:: System.Xml.Linq.dll

組件:: netstandard.dll

來源:: Extensions.cs

來源:: Extensions.cs

來源:: Extensions.cs

來源:: Extensions.cs

來源:: Extensions.cs

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

傳回來源集合中每個文件和專案之子代節點的集合。

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;

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)

類型參數

T

source物件類型，受限於 XContainer。

參數

source: IEnumerable<T>

其中 A IEnumerable<T>XContainer 包含了原始集合。

傳回

IEnumerable<XNode>

IEnumerable<T>一個來自XNode原始集合中每個文件與元素的後裔節點之一。

範例

以下範例取出兩個元素的集合，然後取回來源集合中每個元素的所有後代節點集合。請注意，該 GrandChild 元素的屬性並未以節點形式呈現。

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

此範例會產生下列輸出：

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

以下是相同的範例，但此例中 XML 位於命名空間中。欲了解更多資訊，請參閱 XML 命名空間工作。

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

此範例會產生下列輸出：

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

備註

此軸擴展方法用於 XDocument 和 XElement 物件。這兩種類型皆源自 XContainer，因此此方法作用於IEnumerable<T>包含原始集合的。XContainer

雖然 Visual Basic 內建了 XML 軸來處理後代元素，但沒有整合的後代節點軸，因此 Visual Basic 使用者必須明確使用此軸方法。

此方法使用延遲執行。

適用於

另請參閱

意見反應

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