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XmlTextReader.Normalization Property

Gets or sets a value indicating whether to normalize white space and attribute values.

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

public bool Normalization { get; set; }

Property Value

Type: System.Boolean
true to normalize; otherwise, false. The default is false.


Setting this property when the reader is closed (ReadState is ReadState.Closed).


In the .NET Framework version 2.0 release, the recommended practice is to create XmlReader instances using the XmlReader.Create method. This allows you to take full advantage of the new features introduced in this release. For more information, see Creating XML Readers.

This property can be changed at any time and takes effect on the next read operation.


If the XmlTextReader is used to construct an XmlValidatingReader, to normalize attribute values, Normalization must be set to true.

If Normalization is set to false, this also disables character range checking for numeric entities. As a result, character entities, such as �, are allowed.

The following describes attribute value normalization:

  • For a character reference, append the referenced character to the attribute value.

  • For an entity reference, recursively process the replacement text of the entity.

  • For a white space character (#x20, #xD, #xA, #x9), append #x20 to the normalized value. (Only a single #x20 is appended for a "#xD#xA" sequence that is part of an external parsed entity or the literal entity value of an internal parsed entity.)

  • Process other characters by appending them to the normalized value.

  • If the declared value is not CDATA, discard any leading and trailing space (#x20) characters and replace sequences of space (#x20) characters with a single space (#x20) character.

The XmlTextReader only performs attribute or CDATA normalization. It does not do DTD-specific normalization unless wrapped within an XmlValidatingReader.

Refer to the W3C XML 1.0 recommendation for further discussion on normalization.

The following example shows reader behavior with normalization turned on and then off.

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

public class Sample{

  public static void Main(){

    // Create the XML fragment to be parsed.
    string xmlFrag  = 
    @"<item attr1='  test A B C
        1 2 3'/>
      <item attr2='&#01;'/>";                         

    // Create the XmlNamespaceManager.
    XmlNamespaceManager nsmgr = new XmlNamespaceManager(new NameTable());

    // Create the XmlParserContext.
    XmlParserContext context = new XmlParserContext(null, nsmgr, null, XmlSpace.Preserve);

    // Create the reader.
    XmlTextReader reader = new XmlTextReader(xmlFrag, XmlNodeType.Element, context);

    // Show attribute value normalization.
    reader.Normalization = false;
    Console.WriteLine("Attribute value:{0}", reader.GetAttribute("attr1"));
    reader.Normalization = true;
    Console.WriteLine("Attribute value:{0}", reader.GetAttribute("attr1"));

    // Set Normalization back to false.  This allows the reader to accept
    // character entities in the &#00; to &#20; range.  If Normalization had
    // been set to true, character entities in this range throw an exception.
    reader.Normalization = false;
    Console.WriteLine("Attribute value:{0}", reader.GetAttribute("attr2"));

    // Close the reader.


.NET Framework

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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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