XmlTextReader.ReadAttributeValue 方法

定義

命名空間:

System.Xml

組件:

netstandard.dll, System.Xml.ReaderWriter.dll

來源:

XmlTextReader.cs

將屬性值解析成一個或多個 Text、 EntityReference或 EndEntity 節點。

public:
 override bool ReadAttributeValue();

public override bool ReadAttributeValue();

override this.ReadAttributeValue : unit -> bool

Public Overrides Function ReadAttributeValue () As Boolean

傳回

Boolean

true 如果有節點需要回傳的話。

false 如果讀取器在初始呼叫時未位於屬性節點上，或所有屬性值都已被讀取。

空屬性，例如 ， misc=""會以一個節點回傳 true ，其值為 String.Empty。

範例

以下範例讀取一個屬性，並包含文字節點與實體節點。

using System;
using System.IO;
using System.Xml;

public class Sample
{
  public static void Main()
  {
    XmlTextReader reader = null;

    try
    {
       //Create the XML fragment to be parsed.
       string xmlFrag ="<book genre='novel' misc='sale-item &h; 1987'></book>";

       //Create the XmlParserContext.
       XmlParserContext context;
       string subset = "<!ENTITY h 'hardcover'>";
       context = new XmlParserContext(null, null, "book", null, null, subset, "", "", XmlSpace.None);

       //Create the reader.
       reader = new XmlTextReader(xmlFrag, XmlNodeType.Element, context);

       //Read the misc attribute. The attribute is parsed
       //into multiple text and entity reference nodes.
       reader.MoveToContent();
       reader.MoveToAttribute("misc");
       while (reader.ReadAttributeValue()){
          if (reader.NodeType==XmlNodeType.EntityReference)
            Console.WriteLine("{0} {1}", reader.NodeType, reader.Name);
          else
             Console.WriteLine("{0} {1}", reader.NodeType, reader.Value);
        }
     }
     finally
     {
        if (reader != null)
          reader.Close();
      }
  }
} // End class

Imports System.IO
Imports System.Xml

Public Class Sample

    Public Shared Sub Main()

        Dim reader As XmlTextReader = Nothing

        Try
            ' Create the XML fragment to be parsed.
            Dim xmlFrag As String = "<book genre='novel' misc='sale-item &h; 1987'></book>"
 
            Dim subset As String = "<!ENTITY h 'hardcover'>"
            ' Create the XmlParserContext.
            Dim context As New XmlParserContext(Nothing, Nothing, "book", Nothing, Nothing, subset, "", "", XmlSpace.None)
        
            'Create the reader.
            reader = New XmlTextReader(xmlFrag, XmlNodeType.Element, context)
  
            'Read the misc attribute. The attribute is parsed
            'into multiple text and entity reference nodes.
            reader.MoveToContent()
            reader.MoveToAttribute("misc")
            While (reader.ReadAttributeValue())
                If (reader.NodeType = XmlNodeType.EntityReference)
                    Console.WriteLine($"{reader.NodeType} {reader.Name}")
                Else
                    Console.WriteLine($"{reader.NodeType} {reader.Value}")
                End If
            End While

        Finally 
            If reader IsNot Nothing
                reader.Close()
            End if
        End Try
    End Sub
End Class

備註

備註

建議您使用 XmlReader 方法來建立XmlReader.Create實例，以利用新功能。

呼叫後 MoveToAttribute 使用此方法，讀取構成屬性值的文字或實體參考節點。 屬性值節點的 是 Depth 1 加上屬性節點的深度;當你進入或退出一般實體參考時，深度會增加或減少一。

另請參閱

• XmlReader