XmlAttributeEventHandler Delegate

Represents the method that handles the UnknownAttribute

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

'Declaration
Public Delegate Sub XmlAttributeEventHandler ( _
	sender As Object, _
	e As XmlAttributeEventArgs _
)
'Usage
Dim instance As New XmlAttributeEventHandler(AddressOf HandlerMethod)
/** @delegate */
public delegate void XmlAttributeEventHandler (
	Object sender, 
	XmlAttributeEventArgs e
)
JScript supports the use of delegates, but not the declaration of new ones.

Parameters

sender

The source of the event.

e

An XmlAttributeEventArgs that contains the event data.

When you create an XmlAttributeEventHandler delegate, you identify the method that handles the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Events and Delegates.

The UnknownAttribute event occurs only when an object is being deserialized with the Deserialize method.

The following example deserializes a class named Group from a file named UnknownAttributes.xml. Whenever an element is found in the file that has no corresponding member in the class, the UnknownAttribute event occurs. To try the example, paste the following XML code into a file named UnknownAttributes.xml.

 <?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" GroupType = 'Technical' GroupNumber = '42' GroupBase = 'Red'>
   <GroupName>MyGroup</GroupName>
 </Group>
Imports System
Imports System.IO
Imports System.Xml.Serialization
Imports System.Xml
Imports System.Xml.Schema
Imports Microsoft.VisualBasic

Public Class Group
   Public GroupName As String 
End Class

Public Class Test
   Shared Sub Main()
      Dim t As Test = new Test()
      ' Deserialize the file containing unknown elements.
      t.DeserializeObject("UnknownAttributes.xml")
   End Sub

   Private Sub Serializer_UnknownAttribute _
   (sender As Object , e As XmlAttributeEventArgs)
      Console.WriteLine("Unknown Attribute")
      Console.WriteLine(ControlChars.Tab & e.Attr.Name + " " & e.Attr.InnerXml)
      Console.WriteLine(ControlChars.Tab & e.LineNumber & ":"  & e.LineNumber)
      Console.WriteLine(ControlChars.Tab & e.LinePosition & ":"   & e.LinePosition)
      
      Dim x As Group = CType( e.ObjectBeingDeserialized, Group)
      Console.WriteLine (x.GroupName)
      Console.WriteLine (sender.ToString())
   End Sub
   
   Private Sub DeserializeObject(filename As String)
      Dim ser As XmlSerializer = new XmlSerializer(GetType(Group))
      ' Add a delegate to handle unknown element events.
      AddHandler ser.UnknownAttribute, _
      AddressOf Serializer_UnknownAttribute 
      ' A FileStream is needed to read the XML document.
     Dim fs As FileStream  = new FileStream(filename, FileMode.Open)
     Dim g  As Group = CType(ser.Deserialize(fs),Group)
     fs.Close()
   End Sub
End Class

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

public class Group
{
    public String groupName;
} //Group

public class Test
{
    public static void main(String[] args)
    {
        Test t = new Test();
        // Deserialize the file containing unknown elements.
        t.DeserializeObject("UnknownAttributes.xml");
    } //main

    private void Serializer_UnknownAttribute(Object sender,
        XmlAttributeEventArgs e)
    {
        Console.WriteLine("Unknown Attribute");
        Console.WriteLine("\t" + e.get_Attr().get_Name() + " "
            + e.get_Attr().get_InnerXml());
        Console.WriteLine("\t LineNumber: " + e.get_LineNumber());
        Console.WriteLine("\t LinePosition: " + e.get_LinePosition());

        Group x = (Group)e.get_ObjectBeingDeserialized();
        Console.WriteLine(x.groupName);
        Console.WriteLine(sender.ToString());
    } //Serializer_UnknownAttribute

    private void DeserializeObject(String filename)
    {
        XmlSerializer ser = new XmlSerializer(Group.class.ToType());

        // Add a delegate to handle unknown element events.
        ser.add_UnknownAttribute(new XmlAttributeEventHandler
            (Serializer_UnknownAttribute));

        // A FileStream is needed to read the XML document.
        FileStream fs = new FileStream(filename, FileMode.Open);
        Group g = (Group)ser.Deserialize(fs);
        fs.Close();
    } //DeserializeObject
} //Test

Windows 98, Windows 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 .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

Community Additions

ADD
Show: