XmlNodeReader.ResolveEntity 方法

定義

命名空間:

System.Xml

組件:

System.Xml.ReaderWriter.dll

組件:

System.Xml.dll

組件:

netstandard.dll

解析 EntityReference 節點的實體參考。

public:
 override void ResolveEntity();

public override void ResolveEntity ();

override this.ResolveEntity : unit -> unit

Public Overrides Sub ResolveEntity ()

例外狀況

InvalidOperationException

讀取器不在 EntityReference 節點上。

範例

下列範例會使用 ResolveEntity 展開一般實體。

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
   XmlNodeReader^ reader = nullptr;
   try
   {
      
      //Create and load an XML document. 
      XmlDocument^ doc = gcnew XmlDocument;
      doc->LoadXml( "<!DOCTYPE book [<!ENTITY h 'hardcover'>]>"
      "<book>"
      "<title>Pride And Prejudice</title>"
      "<misc>&h;</misc>"
      "</book>" );
      
      //Create the reader.
      reader = gcnew XmlNodeReader( doc );
      reader->MoveToContent(); //Move to the root element.
      reader->Read(); //Move to title start tag.
      reader->Skip(); //Skip the title element.
      
      //Read the misc start tag.  The reader is now positioned on
      //the entity reference node.
      reader->ReadStartElement();
      
      //You must call ResolveEntity to expand the entity reference.
      //The entity replacement text is then parsed and returned as a child node.
      Console::WriteLine( "Expand the entity..." );
      reader->ResolveEntity();
      Console::WriteLine( "The entity replacement text is returned as a text node." );
      reader->Read();
      Console::WriteLine( "NodeType: {0} Value: {1}", reader->NodeType, reader->Value );
      Console::WriteLine( "An EndEntity node closes the entity reference scope." );
      reader->Read();
      Console::WriteLine( "NodeType: {0} Name: {1}", reader->NodeType, reader->Name );
   }
   finally
   {
      if ( reader != nullptr )
            reader->Close();
   }

}

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

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

     try
     {
       //Create and load an XML document.
       XmlDocument doc = new XmlDocument();
       doc.LoadXml("<!DOCTYPE book [<!ENTITY h 'hardcover'>]>" +
                   "<book>" +
                   "<title>Pride And Prejudice</title>" +
                   "<misc>&h;</misc>" +
                   "</book>");

       //Create the reader.
       reader = new XmlNodeReader(doc);

       reader.MoveToContent();  //Move to the root element.
       reader.Read();  //Move to title start tag.
       reader.Skip();  //Skip the title element.

       //Read the misc start tag.  The reader is now positioned on
       //the entity reference node.
       reader.ReadStartElement();

       //You must call ResolveEntity to expand the entity reference.
       //The entity replacement text is then parsed and returned as a child node.
       Console.WriteLine("Expand the entity...");
       reader.ResolveEntity();

       Console.WriteLine("The entity replacement text is returned as a text node.");
       reader.Read();
       Console.WriteLine("NodeType: {0} Value: {1}", reader.NodeType ,reader.Value);

       Console.WriteLine("An EndEntity node closes the entity reference scope.");
       reader.Read();
       Console.WriteLine("NodeType: {0} Name: {1}", reader.NodeType,reader.Name);
    }
    finally
    {
       if (reader != null)
         reader.Close();
    }
  }
}

Option Explicit
Option Strict

Imports System.IO
Imports System.Xml

Public Class Sample
    
    Public Shared Sub Main()
        Dim reader As XmlNodeReader = Nothing
        
        Try
            'Create and load an XML document. 
            Dim doc As New XmlDocument()
            doc.LoadXml("<!DOCTYPE book [<!ENTITY h 'hardcover'>]>" & _
                        "<book>" & _
                        "<title>Pride And Prejudice</title>" & _
                        "<misc>&h;</misc>" & _
                        "</book>")
            
            'Create the reader.
            reader = New XmlNodeReader(doc)
            
            reader.MoveToContent() 'Move to the root element.
            reader.Read() 'Move to title start tag.
            reader.Skip() 'Skip the title element.
            'Read the misc start tag.  The reader is now positioned on
            'the entity reference node.
            reader.ReadStartElement()
            
            'You must call ResolveEntity to expand the entity reference.
            'The entity replacement text is then parsed and returned as a child node.
            Console.WriteLine("Expand the entity...")
            reader.ResolveEntity()
            
            Console.WriteLine("The entity replacement text is returned as a text node.")
            reader.Read()
            Console.WriteLine("NodeType: {0} Value: {1}", reader.NodeType, reader.Value)
            
            Console.WriteLine("An EndEntity node closes the entity reference scope.")
            reader.Read()
            Console.WriteLine("NodeType: {0} Name: {1}", reader.NodeType, reader.Name)
        
        Finally
            If Not (reader Is Nothing) Then
                reader.Close()
            End If
        End Try
    End Sub
End Class

備註

注意

在 .NET Framework 2.0 中，建議的做法是使用 XmlReaderSettings 類別和 Create 方法建立 XmlReader 實例。 這可讓您充分利用.NET Framework中引進的所有新功能。 如需詳細資訊，請參閱參考頁面中的 XmlReader 一節。

如果讀取器位於 EntityReference 節點 () XmlNodeType.EntityReference ，如果在 Read 呼叫此方法之後呼叫 ，則會剖析實體取代文字。 實體取代文字完成時， EndEntity 會傳回節點以關閉實體參考範圍。

注意

呼叫此方法之後，如果實體是屬性值的一部分，您必須呼叫 以逐步執行 ReadAttributeValue 實體。