XmlValidatingReader.ResolveEntity メソッド

.NET Framework クラス ライブラリ リファレンス

XmlValidatingReader.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 XmlValidatingReader

instance.ResolveEntity

C#

public override void ResolveEntity ()

C++

public:
virtual void ResolveEntity () override

J#

public void ResolveEntity ()

JScript

public override function ResolveEntity ()

例外

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

解説

メモ
Microsoft .NET Framework version 2.0 では、XmlValidatingReader クラスは使用されなくなりました。検証を実行する XmlReader のインスタンスは、XmlReaderSettings クラスおよび Create メソッドを使用して作成できます。詳細については、「XmlReader による XML データの検証」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終了した後は、エンティティ参照スコープを閉じる EndEntity ノードが返されます。

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 Strict
Option Explicit

Imports System
Imports System.IO
Imports System.Xml

Public Class Sample
   
   Public Shared Sub Main()
      Dim reader As XmlValidatingReader = Nothing
      Dim txtreader As XmlTextReader = Nothing
      
      Try
         'Create and load the XmlTextReader with the XML file. 
         txtreader = New XmlTextReader("book1.xml")
         txtreader.WhitespaceHandling = WhitespaceHandling.None
         
         'Create the XmlValidatingReader over the XmlTextReader.
         'Set the reader to not expand general entities.
         reader = New XmlValidatingReader(txtreader)
         reader.ValidationType = ValidationType.None
         reader.EntityHandling = EntityHandling.ExpandCharEntities
         
         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()
         
         'Because EntityHandling is set to ExpandCharEntities, you must
 call 
         'ResolveEntity to expand the entity.  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

C#

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

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

     try
     {
       //Create and load the XmlTextReader with the XML file. 
       txtreader = new XmlTextReader("book1.xml");
       txtreader.WhitespaceHandling = WhitespaceHandling.None;

       //Create the XmlValidatingReader over the XmlTextReader.
       //Set the reader to not expand general entities.
       reader = new XmlValidatingReader(txtreader);
       reader.ValidationType = ValidationType.None;
       reader.EntityHandling = EntityHandling.ExpandCharEntities;

       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(); 

       //Because EntityHandling is set to ExpandCharEntities, you must
 call 
       //ResolveEntity to expand the entity.  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()
{
   XmlValidatingReader^ reader = nullptr;
   XmlTextReader^ txtreader = nullptr;
   try
   {
      
      //Create and load the XmlTextReader with the XML file. 
      txtreader = gcnew XmlTextReader( "book1.xml" );
      txtreader->WhitespaceHandling = WhitespaceHandling::None;
      
      //Create the XmlValidatingReader over the XmlTextReader.
      //Set the reader to not expand general entities.
      reader = gcnew XmlValidatingReader( txtreader );
      reader->ValidationType = ValidationType::None;
      reader->EntityHandling = EntityHandling::ExpandCharEntities;
      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();
      
      //Because EntityHandling is set to ExpandCharEntities, you must
 call 
      //ResolveEntity to expand the entity.  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();
   }

}

J#

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

public class Sample
{
    public static void main(String[]
 args)
    {
        XmlValidatingReader reader = null;
        XmlTextReader txtReader = null;
        try {
            //Create and load the XmlTextReader with the XML file. 
            txtReader = new XmlTextReader("book1.xml");
            txtReader.set_WhitespaceHandling(WhitespaceHandling.None);

            //Create the XmlValidatingReader over the XmlTextReader.
            //Set the reader to not expand general entities.
            reader = new XmlValidatingReader(txtReader);
            reader.set_ValidationType(ValidationType.None);
            reader.set_EntityHandling(EntityHandling.ExpandCharEntities);

            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();

            //Because EntityHandling is set to ExpandCharEntities, you
  
            //must call ResolveEntity to expand the entity.  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

この例では、入力として、book1.xml というファイルを使用しています。

<?xml version='1.0' ?>
<!DOCTYPE book [<!ENTITY
 h 'hardcover'>]>
<book>
  <title>Pride And
 Prejudice</title>
  <misc>&h;</misc>
</book>

プラットフォーム

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0

参照

関連項目
XmlValidatingReader クラス
XmlValidatingReader メンバ
System.Xml 名前空間
EntityHandling 列挙体
その他の技術情報
XmlReader による XML の読み取り