XmlNodeReader.ResolveEntity メソッドとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

XmlNodeReader.ResolveEntity メソッド

EntityReference ノードのエンティティ参照を解決します。

名前空間: System.Xml
アセンブリ: System.Xml (system.xml.dll 内)
構文

Visual Basic (宣言)

Public Overrides Sub ResolveEntity

Visual Basic (使用法)

Dim instance As XmlNodeReader

instance.ResolveEntity

public override void ResolveEntity ()

C++

public:
virtual void ResolveEntity () override

public void ResolveEntity ()

JScript

public override function ResolveEntity ()

例外

例外の種類	条件
InvalidOperationException	リーダーが EntityReference ノードに配置されていません。

解説

メモ
Microsoft .NET Framework version 2.0 では、XmlReaderSettings クラスと Create メソッドを使用して XmlReader インスタンスを作成することをお勧めします。これにより、.NET Framework で導入されたすべての新機能を十分に活用できます。詳細については、「XML リーダーの作成」を参照してください。

リーダーが EntityReference ノード (XmlNodeType.EntityReference) に配置されている場合は、このメソッドを呼び出した後に Read を呼び出すと、エンティティ置換テキストが解析されます。エンティティ置換テキストが完成すると、EndEntity ノードが返され、エンティティ参照スコープを閉じます。

メモ
このメソッドを呼び出すと、エンティティが属性値の一部の場合は、ReadAttributeValue を呼び出して、エンティティを調べる必要があります。

使用例

ResolveEntity を使用して一般エンティティを展開する例を次に示します。

Visual Basic

Option Explicit
Option Strict

Imports System
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 'Main
End Class 'Sample

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();
    }
  }
}

C++

#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();
   }

}

import System.*;
import System.IO.*;
import System.Xml.*;

public class Sample
{
    public static void main(String[]
 args)
    {
        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.get_NodeType()
,
                reader.get_Value());

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