根據名稱或索引擷取的未排序節點

根據全球資訊網協會 (W3C) 規格中的說明，XmlNamedNodeMap 是一種 NamedNodeMap，若所處理之未排序節點集具有根據名稱或索引參考節點的功能，就必須使用它。存取 XmlNamedNodeMap 的唯一方法，是當 XmlNamedNodeMap 經由方法或屬性傳回時。有三種方法或屬性會傳回 XmlNamedNodeMap：

• XmlElement.Attributes

• XmlDocumentType.Entities

• XmlDocumentType.Notations

例如，XmlDocumentType.Entities 屬性會取得文件類型宣告中宣告的 XmlEntity 節點之集合。這個集合會以 XmlNamedNodeMap 傳回，而且您可以使用 Count 屬性重複集合並且顯示實體資訊。如需重複 XmlNamedNodeMap 的範例，請參閱 XmlDocumentType.Entities 屬性。

XmlAttributeCollection 衍生自 XmlNamedNodeMap 而且只有其屬性可以修改，標記法和實體則是唯讀。使用屬性的 XmlNamedNodeMap，您可以根據它們的 XML 名稱取得這些屬性的節點。這提供簡單的方法來操作項目節點上的屬性集合。這與直接使用 XmlNodeList 相反，後者也實作 IEnumerable 介面，但是是使用索引存取子 (Accessor) 而不是字串。RemoveNamedItem 和 SetNamedItem 方法只能用於 XmlAttributeCollection。從屬性集合加入或移除，無論是使用 AttributeCollection 或 XmlNamedNodeMap 實作，都會在項目上修改屬性集合。下列程式碼範例將說明如何移動屬性及建立新屬性。

Imports System
Imports System.Xml

Class test

    Public Shared Sub Main()
        Dim doc As New XmlDocument()
        doc.LoadXml("<root> <child1 attr1='val1' attr2='val2'> text1 </child1> <child2 attr3='val3'> text2 </child2> </root> ")

        ' Get the attributes of node "child2 "
        Dim ac As XmlAttributeCollection = doc.DocumentElement.ChildNodes(1).Attributes

        ' Print out the number of attributes and their names.
        Console.WriteLine(("Number of Attributes: " + ac.Count))
        Dim i As Integer
        For i = 0 To ac.Count - 1
            Console.WriteLine((i + 1 + ".  Attribute Name: '" + ac(i).Name + "'  Attribute Value:  '" + ac(i).Value + "'"))
        Next i
        ' Get the 'attr1' from child1.
        Dim attr As XmlAttribute = doc.DocumentElement.ChildNodes(0).Attributes(0)

        ' Add this attribute to the attributecollection "ac".
        ac.SetNamedItem(attr)

        ''attr1' will be removed from 'child1' and added to 'child2'.
        ' Print out the number of attributes and their names.
        Console.WriteLine(("Number of Attributes: " + ac.Count))

        For i = 0 To ac.Count - 1
            Console.WriteLine((i + 1 + ".  Attribute Name: '" + ac(i).Name + "'  Attribute Value:  '" + ac(i).Value + "'"))
        Next i
        ' Create a new attribute and add to the collection.
        Dim attr2 As XmlAttribute = doc.CreateAttribute("attr4")
        attr2.Value = "val4"
        ac.SetNamedItem(attr2)

        ' Print out the number of attributes and their names.
        Console.WriteLine(("Number of Attributes: " + ac.Count))

        For i = 0 To ac.Count - 1
            Console.WriteLine((i + 1 + ".  Attribute Name: '" + ac(i).Name + "'  Attribute Value:  '" + ac(i).Value + "'"))
        Next i
    End Sub 'Main
End Class 'test

using System;
using System.Xml;
class test {
    public static void Main() {
        XmlDocument doc = new XmlDocument();
        doc.LoadXml( "<root> <child1 attr1='val1' attr2='val2'> text1 </child1> <child2 attr3='val3'> text2 </child2> </root> " );

        // Get the attributes of node "child2"
        XmlAttributeCollection ac = doc.DocumentElement.ChildNodes[1].Attributes;

        // Print out the number of attributes and their names.
        Console.WriteLine( "Number of Attributes: "+ac.Count );
        for( int i = 0; i < ac.Count; i++ )
            Console.WriteLine( (i+1) + ".  Attribute Name: '" +ac[i].Name+ "'  Attribute Value:  '"+ ac[i].Value +"'" ); 

        // Get the 'attr1' from child1.
        XmlAttribute attr = doc.DocumentElement.ChildNodes[0].Attributes[0];

        // Add this attribute to the attributecollection "ac".
        ac.SetNamedItem( attr );

        // 'attr1' will be removed from 'child1' and added to 'child2'.
        // Print out the number of attributes and their names.
        Console.WriteLine( "Number of Attributes: "+ac.Count );        
        for( int i = 0; i < ac.Count; i++ )
            Console.WriteLine( (i+1) + ".  Attribute Name: '" +ac[i].Name+ "'  Attribute Value:  '"+ ac[i].Value +"'" ); 

        // Create a new attribute and add to the collection.
        XmlAttribute attr2 = doc.CreateAttribute( "attr4" );
        attr2.Value = "val4";
        ac.SetNamedItem( attr2 );

        // Print out the number of attributes and their names.
        Console.WriteLine( "Number of Attributes: "+ac.Count );        
        for( int i = 0; i < ac.Count; i++ )
            Console.WriteLine( (i+1) + ".  Attribute Name: '" +ac[i].Name+ "'  Attribute Value:  '"+ ac[i].Value +"'" );         
       
    }
}

若要查看會顯示從 AttributeCollection 移除屬性的其他程式碼範例，請參閱 XmlNamedNodeMap.RemoveNamedItem 方法。如需方法和屬性的詳細資訊，請參閱 XmlNamedNodeMap 成員。

請參閱

概念

XML 文件物件模型 (DOM)