Extensions.Ancestors 方法

定义

命名空间:: System.Xml.Linq

程序集:: System.Xml.Linq.dll, System.Xml.XDocument.dll

程序集:: netstandard.dll, System.Xml.XDocument.dll

程序集:: System.Xml.XDocument.dll

程序集:: System.Xml.Linq.dll

程序集:: netstandard.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

返回一个元素集合，其中包含源集合中每个节点的上级。

重载

名称	说明
Ancestors<T>(IEnumerable<T>)	返回一个元素集合，其中包含源集合中每个节点的上级。
Ancestors<T>(IEnumerable<T>, XName)	返回一个筛选的元素集合，其中包含源集合中每个节点的上级。集合中仅包含具有匹配 XName 的元素。

注解

如果源集合中的多个节点具有相同的上级，则上级将多次包含在结果集合中。若要避免这种情况，请使用 Distinct 该方法。

此方法使用延迟执行。

Ancestors<T>(IEnumerable<T>)

Source:: Extensions.cs

Source:: Extensions.cs

Source:: Extensions.cs

Source:: Extensions.cs

Source:: Extensions.cs

返回一个元素集合，其中包含源集合中每个节点的上级。

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

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

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

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

<Extension()>
Public Function Ancestors(Of T As XNode) (source As IEnumerable(Of T)) As IEnumerable(Of XElement)

类型参数

T

中 source对象的类型，受 XNode约束。

参数

source: IEnumerable<T>

IEnumerable<T>其中一个XNode包含源集合。

IEnumerable<XElement>

IEnumerable<T>其中一个XElement包含源集合中每个节点的上级。

示例

以下示例检索大孙元素的集合。然后，它使用此轴方法检索集合中所有元素的所有上级。

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().Distinct()
    select el;

Console.WriteLine("");
Console.WriteLine("Ancestors");
Console.WriteLine("----");
foreach (XElement de in allAncestors)
    Console.WriteLine(de.Name);

Dim xmlTree As XElement = _
    <Root>
        <Child1>
            <GrandChild1>
                <GreatGrandChild1>content</GreatGrandChild1>
            </GrandChild1>
        </Child1>
        <Child2>
            <GrandChild2>
                <GreatGrandChild2>content</GreatGrandChild2>
            </GrandChild2>
        </Child2>
    </Root>

Dim greatGrandChildren = From el In xmlTree.Descendants _
                         Where el.Name.LocalName.StartsWith("Great") _
                         Select el

Console.WriteLine("Great Grand Children Elements")
Console.WriteLine("----")

For Each de As XElement In greatGrandChildren
    Console.WriteLine(de.Name)
Next

Dim allAncestors = From el In greatGrandChildren.Ancestors.Distinct _
                   Select el

Console.WriteLine("")
Console.WriteLine("Ancestors")
Console.WriteLine("----")

For Each de As XElement In allAncestors
    Console.WriteLine(de.Name)
Next

此示例生成以下输出：

Great Grand Children Elements
----
GreatGrandChild1
GreatGrandChild2

Ancestors
----
GrandChild1
Child1
Root
GrandChild2
Child2

下面是相同的示例，但在这种情况下，XML 位于命名空间中。有关详细信息，请参阅 “使用 XML 命名空间”。

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().Distinct()
    select el;

Console.WriteLine("");
Console.WriteLine("Ancestors");
Console.WriteLine("----");
foreach (XElement de in allAncestors)
    Console.WriteLine(de.Name);

Imports <xmlns="http://www.adventure-works.com">

Module Module1
    Sub Main()
        Dim xmlTree As XElement = _
            <Root>
                <Child1>
                    <GrandChild1>
                        <GreatGrandChild1>content</GreatGrandChild1>
                    </GrandChild1>
                </Child1>
                <Child2>
                    <GrandChild2>
                        <GreatGrandChild2>content</GreatGrandChild2>
                    </GrandChild2>
                </Child2>
            </Root>

        Dim greatGrandChildren = From el In xmlTree.Descendants _
                                 Where el.Name.LocalName.StartsWith("Great") _
                                 Select el

        Console.WriteLine("Great Grand Children Elements")
        Console.WriteLine("----")

        For Each de As XElement In greatGrandChildren
            Console.WriteLine(de.Name)
        Next

        Dim allAncestors = From el In greatGrandChildren.Ancestors.Distinct _
                           Select el

        Console.WriteLine("")
        Console.WriteLine("Ancestors")
        Console.WriteLine("----")

        For Each de As XElement In allAncestors
            Console.WriteLine(de.Name)
        Next
    End Sub
End Module

此示例生成以下输出：

Great Grand Children Elements
----
{http://www.adventure-works.com}GreatGrandChild1
{http://www.adventure-works.com}GreatGrandChild2

Ancestors
----
{http://www.adventure-works.com}GrandChild1
{http://www.adventure-works.com}Child1
{http://www.adventure-works.com}Root
{http://www.adventure-works.com}GrandChild2
{http://www.adventure-works.com}Child2

注解

如果源集合中的多个节点具有相同的上级，则上级将多次包含在结果集合中。若要避免这种情况，请使用 Distinct 该方法。

此方法使用延迟执行。

另请参阅

适用于

Ancestors<T>(IEnumerable<T>, XName)

Source:: Extensions.cs

Source:: Extensions.cs

Source:: Extensions.cs

Source:: Extensions.cs

Source:: Extensions.cs

返回一个筛选的元素集合，其中包含源集合中每个节点的上级。集合中仅包含具有匹配 XName 的元素。

public:
generic <typename T>
 where T : System::Xml::Linq::XNode[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable<System::Xml::Linq::XElement ^> ^ Ancestors(System::Collections::Generic::IEnumerable<T> ^ source, System::Xml::Linq::XName ^ name);

public static System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement> Ancestors<T>(this System.Collections.Generic.IEnumerable<T> source, System.Xml.Linq.XName name) where T : System.Xml.Linq.XNode;

public static System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement> Ancestors<T>(this System.Collections.Generic.IEnumerable<T?> source, System.Xml.Linq.XName? name) where T : System.Xml.Linq.XNode;

static member Ancestors : seq<'T (requires 'T :> System.Xml.Linq.XNode)> * System.Xml.Linq.XName -> seq<System.Xml.Linq.XElement> (requires 'T :> System.Xml.Linq.XNode)

<Extension()>
Public Function Ancestors(Of T As XNode) (source As IEnumerable(Of T), name As XName) As IEnumerable(Of XElement)

类型参数

T

中 source对象的类型，受 XNode约束。

参数

source: IEnumerable<T>

IEnumerable<T>其中一个XNode包含源集合。

name: XName

要 XName 匹配的。

IEnumerable<XElement>

IEnumerable<T>其中一个XElement包含源集合中每个节点的上级。集合中仅包含具有匹配 XName 的元素。

示例

以下示例检索大孙元素的集合。然后，它使用此轴方法检索集合中与指定 XName元素匹配的所有元素的所有上级。

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);

Dim xmlTree As XElement = _
    <Root>
        <Child1>
            <GrandChild1>
                <GreatGrandChild1>content</GreatGrandChild1>
            </GrandChild1>
        </Child1>
        <Child2>
            <GrandChild2>
                <GreatGrandChild2>content</GreatGrandChild2>
            </GrandChild2>
        </Child2>
    </Root>

Dim greatGrandChildren = From el In xmlTree.Descendants _
                         Where el.Name.LocalName.StartsWith("Great") _
                         Select el

Console.WriteLine("Great Grand Children Elements")
Console.WriteLine("----")

For Each de As XElement In greatGrandChildren
    Console.WriteLine(de.Name)
Next

Dim allAncestors = From el In greatGrandChildren.Ancestors("Child1") _
                   Select el

Console.WriteLine("")
Console.WriteLine("Ancestors")
Console.WriteLine("----")

For Each de As XElement In allAncestors
    Console.WriteLine(de.Name)
Next

此示例生成以下输出：

Great Grand Children Elements
----
GreatGrandChild1
GreatGrandChild2

Ancestors
----
Child1

下面是相同的示例，但在这种情况下，XML 位于命名空间中。有关详细信息，请参阅 “使用 XML 命名空间”。

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);

Imports <xmlns="http://www.adventure-works.com">

Module Module1
    Sub Main()
        Dim xmlTree As XElement = _
            <Root>
                <Child1>
                    <GrandChild1>
                        <GreatGrandChild1>content</GreatGrandChild1>
                    </GrandChild1>
                </Child1>
                <Child2>
                    <GrandChild2>
                        <GreatGrandChild2>content</GreatGrandChild2>
                    </GrandChild2>
                </Child2>
            </Root>

        Dim greatGrandChildren = From el In xmlTree.Descendants _
                                 Where el.Name.LocalName.StartsWith("Great") _
                                 Select el

        Console.WriteLine("Great Grand Children Elements")
        Console.WriteLine("----")

        For Each de As XElement In greatGrandChildren
            Console.WriteLine(de.Name)
        Next

        Dim allAncestors = From el In greatGrandChildren.Ancestors(GetXmlNamespace() + "Child1") _
                           Select el

        Console.WriteLine("")
        Console.WriteLine("Ancestors")
        Console.WriteLine("----")

        For Each de As XElement In allAncestors
            Console.WriteLine(de.Name)
        Next
    End Sub
End Module

此示例生成以下输出：

Great Grand Children Elements
----
{http://www.adventure-works.com}GreatGrandChild1
{http://www.adventure-works.com}GreatGrandChild2

Ancestors
----
{http://www.adventure-works.com}Child1

注解

如果源集合中的多个节点具有与匹配 XName相同的上级，则结果集合中将多次包含上级节点。

此方法使用延迟执行。

另请参阅

适用于

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