XPathNavigator.Clone 方法

定义

命名空间:

System.Xml.XPath

程序集:

System.Xml.ReaderWriter.dll

程序集:

System.Xml.XPath.dll

程序集:

System.Xml.dll

程序集:

netstandard.dll

当在派生类中被重写时，创建一个新的 XPathNavigator，它定位到的节点与此 XPathNavigator 定位到的节点相同。

public:
 abstract System::Xml::XPath::XPathNavigator ^ Clone();

public abstract System.Xml.XPath.XPathNavigator Clone ();

abstract member Clone : unit -> System.Xml.XPath.XPathNavigator

Public MustOverride Function Clone () As XPathNavigator

返回

XPathNavigator

一个新的 XPathNavigator，它定位到的节点与此 XPathNavigator 定位到的节点相同。

示例

以下示例获取赫曼·梅尔维尔创作的所有书名。

XPathDocument^ document = gcnew XPathDocument("books.xml");
XPathNavigator^ navigator = document->CreateNavigator();

// Select all books authored by Melville.
XPathNodeIterator^ nodes = navigator->Select("descendant::book[author/last-name='Melville']");

while (nodes->MoveNext())
{
    // Clone the navigator returned by the Current property. 
    // Use the cloned navigator to get the title element.
    XPathNavigator^ clone = nodes->Current->Clone();
    clone->MoveToFirstChild();
    Console::WriteLine("Book title: {0}", clone->Value);
}

XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();

// Select all books authored by Melville.
XPathNodeIterator nodes = navigator.Select("descendant::book[author/last-name='Melville']");

while (nodes.MoveNext())
{
    // Clone the navigator returned by the Current property.
    // Use the cloned navigator to get the title element.
    XPathNavigator clone = nodes.Current.Clone();
    clone.MoveToFirstChild();
    Console.WriteLine("Book title: {0}", clone.Value);
}

Dim document As XPathDocument = New XPathDocument("books.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()

' Select all books authored by Melville.
Dim nodes As XPathNodeIterator = navigator.Select("descendant::book[author/last-name='Melville']")

While nodes.MoveNext()
    ' Clone the navigator returned by the Current property. 
    ' Use the cloned navigator to get the title element.
    Dim clone As XPathNavigator = nodes.Current.Clone()
    clone.MoveToFirstChild()
    Console.WriteLine("Book title: {0}", clone.Value)
End While

该示例使用 books.xml 文件作为输入。

<?xml version="1.0" encoding="utf-8" ?>   
<bookstore>  
    <book genre="autobiography" publicationdate="1981-03-22" ISBN="1-861003-11-0">  
        <title>The Autobiography of Benjamin Franklin</title>  
        <author>  
            <first-name>Benjamin</first-name>  
            <last-name>Franklin</last-name>  
        </author>  
        <price>8.99</price>  
    </book>  
    <book genre="novel" publicationdate="1967-11-17" ISBN="0-201-63361-2">  
        <title>The Confidence Man</title>  
        <author>  
            <first-name>Herman</first-name>  
            <last-name>Melville</last-name>  
        </author>  
        <price>11.99</price>  
    </book>  
    <book genre="philosophy" publicationdate="1991-02-15" ISBN="1-861001-57-6">  
        <title>The Gorgias</title>  
        <author>  
            <name>Plato</name>  
        </author>  
        <price>9.99</price>  
    </book>  
</bookstore>  

注解

该方法 Clone 与 . XPathNodeIterator. 一XPathNodeIterator个用于循环访问所选节点集，并包含返回Current位于上下文节点上XPathNodeIterator的属性XPathNavigator。 但是， XPathNavigator 属性返回 Current 的不能用于移离节点集。 而是克隆返回 XPathNavigator 的，并使用克隆的导航器执行任何其他移动。

克隆 XPathNavigator 不受对原始 XPathNavigator副本的后续更改的影响。