XmlSerializer.UnknownNode Event

Occurs when the XmlSerializer encounters an XML node of unknown type during deserialization.

Namespace: System.Xml.Serialization
Assembly: System.Xml (in system.xml.dll)

'Declaration
Public Event UnknownNode As XmlNodeEventHandler
'Usage
Dim instance As XmlSerializer
Dim handler As XmlNodeEventHandler

AddHandler instance.UnknownNode, handler

/** @event */
public void add_UnknownNode (XmlNodeEventHandler value)

/** @event */
public void remove_UnknownNode (XmlNodeEventHandler value)

In JScript, you can handle the events defined by a class, but you cannot define your own.
Not applicable.

By default, after calling the Deserialize method, the XmlSerializer ignores XML nodes of unknown types. However, you can use this event to handle such node types.

The following example prints the type of any encountered unknown node.

Imports System
Imports System.IO
Imports System.Xml
Imports System.Xml.Serialization

Public Class Group
   ' Only the GroupName field will be known.
   Public GroupName As String
End Class

Public Class Test
   Shared Sub Main()
      Dim t As Test = New Test()
      t.DeserializeObject("UnknownNodes.xml")
   End Sub

   Private Sub DeserializeObject(filename As String )
      Dim mySerializer As XmlSerializer  = New XmlSerializer(GetType(Group))
      Dim fs As FileStream = New FileStream(filename, FileMode.Open)
      AddHandler mySerializer.UnknownNode, _
      AddressOf serializer_UnknownNode
      Dim myGroup As Group = _
      CType(mySerializer.Deserialize(fs), Group)
      fs.Close()
   End Sub
   
   Private Sub serializer_UnknownNode _
   (sender As object , e As XmlNodeEventArgs )
      Console.WriteLine _
      ("UnknownNode Name: {0}", e.Name)
      Console.WriteLine _
      ("UnknownNode LocalName: {0}" ,e.LocalName)
      Console.WriteLine _
      ("UnknownNode Namespace URI: {0}", e.NamespaceURI)
      Console.WriteLine _
      ("UnknownNode Text: {0}", e.Text)

      Dim myNodeType As XmlNodeType = e.NodeType
      Console.WriteLine("NodeType: {0}", myNodeType)
 
      Dim myGroup As Group = CType(e.ObjectBeingDeserialized, Group)
      Console.WriteLine("GroupName: {0}", myGroup.GroupName)
      Console.WriteLine()
   End Sub
End Class
' Paste this XML into a file named UnknownNodes:
'<?xml version="1.0" encoding="utf-8"?>
'<Group xmlns:xsi="http:'www.w3.org/2001/XMLSchema-instance" 

'xmlns:xsd="http:'www.w3.org/2001/XMLSchema" xmlns:coho = "http:'www.cohowinery.com" 

'xmlns:cp="http:'www.cpandl.com">
'   <coho:GroupName>MyGroup</coho:GroupName>
'   <cp:GroupSize>Large</cp:GroupSize>
'   <cp:GroupNumber>444</cp:GroupNumber>
'   <coho:GroupBase>West</coho:GroupBase>
'   <coho:ThingInfo>
'      <Number>1</Number>
'      <Name>Thing1</Name>
'      <Elmo>
'         <Glue>element</Glue>
'      </Elmo>
'  </coho:ThingInfo>
'/Group>

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

public class Group
{
    // Only the GroupName field will be known.
    public String groupName;
} //Group

public class Test
{
    public static void main(String[] args)
    {
        Test t = new Test();
        t.DeserializeObject("UnknownNodes.xml");
    } //main

    private void DeserializeObject(String filename)
    {
        XmlSerializer mySerializer = new XmlSerializer(Group.class.ToType());
        FileStream fs = new FileStream(filename, FileMode.Open);
        mySerializer.add_UnknownNode(new XmlNodeEventHandler
            (SerializerUnknownNode));
        Group myGroup = (Group)mySerializer.Deserialize(fs);
        fs.Close();
    } //DeserializeObject

    private void SerializerUnknownNode(Object sender, XmlNodeEventArgs e)
    {
        Console.WriteLine("UnknownNode Name: {0}", e.get_Name());
        Console.WriteLine("UnknownNode LocalName: {0}", e.get_LocalName());
        Console.WriteLine("UnknownNode Namespace URI: {0}",
            e.get_NamespaceURI());
        Console.WriteLine("UnknownNode Text: {0}", e.get_Text());

        XmlNodeType myNodeType = e.get_NodeType();
        Console.WriteLine("NodeType: {0}", myNodeType);

        Group myGroup = (Group)e.get_ObjectBeingDeserialized();
        Console.WriteLine("GroupName: {0}", myGroup.groupName);
        Console.WriteLine();
    } //SerializerUnknownNode
} //Test
/* Paste this XML into a file named UnknownNodes:
<?xml version="1.0" encoding="utf-8"?>
<Group xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 

xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:coho = "http://www.cohowinery.com" 

xmlns:cp="http://www.cpandl.com">
   <coho:GroupName>MyGroup</coho:GroupName>
   <cp:GroupSize>Large</cp:GroupSize>
   <cp:GroupNumber>444</cp:GroupNumber>
   <coho:GroupBase>West</coho:GroupBase>
   <coho:ThingInfo>
      <Number>1</Number>
      <Name>Thing1</Name>
      <Elmo>
         <Glue>element</Glue>
      </Elmo>
   </coho:ThingInfo>
</Group>
*/

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0

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