XPathNodeIterator.Current 屬性

定義

命名空間:

System.Xml.XPath

組件:

System.Xml.ReaderWriter.dll

組件:

System.Xml.XPath.dll

組件:

System.Xml.dll

組件:

netstandard.dll

在衍生類別中覆寫時，取得這個 XPathNodeIterator 的 XPathNavigator 物件，該物件位於目前的內容節點上。

public:
 abstract property System::Xml::XPath::XPathNavigator ^ Current { System::Xml::XPath::XPathNavigator ^ get(); };

public abstract System.Xml.XPath.XPathNavigator? Current { get; }

public abstract System.Xml.XPath.XPathNavigator Current { get; }

member this.Current : System.Xml.XPath.XPathNavigator

Public MustOverride ReadOnly Property Current As XPathNavigator

屬性值

XPathNavigator

XPathNavigator 物件，位於所選取節點集的內容節點上。 您必須呼叫 MoveNext() 方法，將 XPathNodeIterator 移至所選取節點集的第一個節點上。

範例

下列範例會使用 Current 物件的 屬性 XPathNodeIterator 和 Clone 類別的 方法 XPathNavigator ，取得 Herman Melville 所撰寫的所有書籍標題。

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

該範例採用 contosoBooks.xml 檔案做為輸入。

<?xml version="1.0" encoding="utf-8" ?>  
<bookstore xmlns="http://www.contoso.com/books">  
    <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>  

備註

您可以使用傳 XPathNavigator 回物件的屬性來取得目前節點上的資訊。 不過，不應該修改傳 XPathNavigator 回的物件。 傳回 XPathNavigator 的物件無法從選取的節點集移開。

或者，您可以使用 類別的 XPathNavigator 方法來複製 XPathNavigator 物件 Clone 。 XPathNavigator然後，複製的物件就可以從選取的節點集移開。 複製物件的這個方法 XPathNavigator 可能會影響 XPath 查詢的效能。

SelectAncestors如果 、 SelectDescendants 和 SelectChildren 方法導致未選取任何節點， Current 則 屬性可能不會指向內容節點。

若要測試是否已選取節點，請使用 Count 屬性，如下列範例所示。

另請參閱

• MoveNext()
• Clone()
• SelectAncestors
• SelectDescendants
• SelectChildren
• Count