XmlValidatingReader.EntityHandling Vlastnost

Definice

Obor názvů:

System.Xml

Sestavení:

System.Xml.ReaderWriter.dll

Zdroj:

XmlValidatingReader.cs

Získá nebo nastaví hodnotu, která určuje, jak čtenář zpracovává entity.

public:
 property System::Xml::EntityHandling EntityHandling { System::Xml::EntityHandling get(); void set(System::Xml::EntityHandling value); };

public System.Xml.EntityHandling EntityHandling { get; set; }

member this.EntityHandling : System.Xml.EntityHandling with get, set

Public Property EntityHandling As EntityHandling

Hodnota vlastnosti

EntityHandling

Jedna z EntityHandling hodnot. Pokud je zadána hodnota ne EntityHandling , použije se výchozí hodnota EntityHandling.ExpandEntities.

Výjimky

ArgumentOutOfRangeException

Byla zadána neplatná hodnota.

Příklady

Následující příklad používá metodu ResolveEntity k rozbalení obecné entity.

#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();
   }

}

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();
    }
  }
}

Option Strict
Option Explicit

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
End Class

V příkladu se jako vstup používá soubor book1.xml, .

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

Poznámky

Poznámka

Třída XmlValidatingReader je zastaralá v rozhraní .NET Framework 2.0. Ověřovací instanci můžete vytvořit XmlReader pomocí XmlReaderSettings třídy a Create metody . Další informace najdete v části Poznámky na XmlReader referenční stránce.

Tuto vlastnost lze změnit a projeví se po dalším Read volání.

Pokud EntityHandling je hodnota nastavená na ExpandCharEntities, hodnoty atributů se normalizují jenom částečně. Čtenář normalizuje každý jednotlivý textový uzel nezávisle na obsahu sousedních referenčních uzlů entit.

Pro ilustraci rozdílu mezi režimy zpracování entit zvažte následující kód XML:

<!DOCTYPE doc [<!ENTITY num "123">]>  
 <doc> &#65; &num; </doc>  

Pokud EntityHandling je nastavená na ExpandEntities uzel elementu "doc", obsahuje jeden textový uzel s rozbaleným textem entity:

Hloubka	Nodetype	Name	Hodnota
1	Text		A 123

Pokud EntityHandling je nastavená hodnota ExpandCharEntitiesa WhitespaceHandling je nastavená na hodnotu Významné nebo Vše, element "doc" rozbalí entitu znaků a vrátí obecnou entitu jako uzel:

Hloubka	Nodetype	Name	Hodnota
1	Text		A
1	EntityReference	num
1	Významnýwhitespace

Viz také

• XmlReader