Export (0) Print
Expand All

XmlValidatingReader.EntityHandling Property

Gets or sets a value that specifies how the reader handles entities.

Namespace:  System.Xml
Assembly:  System.Xml (in System.Xml.dll)

public EntityHandling EntityHandling { get; set; }

Property Value

Type: System.Xml.EntityHandling
One of the EntityHandling values. If no EntityHandling is specified, it defaults to EntityHandling.ExpandEntities.

ExceptionCondition
ArgumentOutOfRangeException

Invalid value was specified.

NoteNote

The XmlValidatingReader class is obsolete in .NET Framework 2.0. You can create a validating XmlReader instance by using the XmlReaderSettings class and the Create method. For more information, see the Remarks section of the XmlReader reference page.

This property can be changed and takes effect after the next Read call.

When EntityHandling is set to ExpandCharEntities, attribute values are only partially normalized. The reader normalizes each individual text node independently from the content of adjacent entity reference nodes.

To illustrate the difference between the entity handling modes consider the following XML:

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

When EntityHandling is set to ExpandEntities the "doc" element node contains one text node with the expanded entity text:

Depth

NodeType

Name

Value

1

Text

A 123

When EntityHandling is set to ExpandCharEntites, and WhitespaceHandling is set to Significant or All, the "doc" element expands the character entity and returns the general entity as a node:

Depth

NodeType

Name

Value

1

Text

A

1

EntityReference

num

1

SignificantWhitespace

The following example uses the ResolveEntity method to expand a general entity.

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();
    }
  }
}

The example uses the file, book1.xml, as input.


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

.NET Framework

Supported in: 4.5.3, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Show:
© 2014 Microsoft