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UnreferencedObjectEventHandler Delegate

Represents the method that handles the UnreferencedObject event of an XmlSerializer.

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

'Declaration
Public Delegate Sub UnreferencedObjectEventHandler ( _
	sender As Object, _
	e As UnreferencedObjectEventArgs _
)

Parameters

sender
Type: System.Object
The source of the event.
e
Type: System.Xml.Serialization.UnreferencedObjectEventArgs
An UnreferencedObjectEventArgs that contains the event data.

When you create an UnreferencedObjectEventHandler 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 UnreferencedObject event occurs only when you call the Deserialize method.

The following example adds an UnreferencedObjectEventHandler to an XmlSerializer. The event is handled by the Serializer_UnreferencedObject method. To run the example, cut and paste the following XML into a file named UnrefObj.xml.

 <wrapper>
   <Group xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" id="id1" n1:GroupName=".NET" xmlns:n1="http://www.cpandl.com">
    </Group>
 <Vehicle id="id2" n1:type="Vehicle" xmlns:n1="http://www.w3.org/2001/XMLSchema-instance">
     <licenseNumber xmlns:q1="http://www.w3.org/2001/XMLSchema" n1:type="q1:string">ABCD</licenseNumber>
   </Vehicle>
 <Vehicle id="id3" n1:type="Vehicle" xmlns:n1="http://www.w3.org/2001/XMLSchema-instance">
     <licenseNumber xmlns:q1="http://www.w3.org/2001/XMLSchema" n1:type="q1:string">1234</licenseNumber>
   </Vehicle>
 </wrapper>

Imports System
Imports System.IO
Imports System.Text
Imports System.Xml
Imports System.Xml.Serialization
Imports System.Xml.Schema

' You must use the SoapIncludeAttribute to inform the XmlSerializer
' that the Vehicle type should be recognized when deserializing.
<SoapInclude(GetType(Vehicle))> _
Public Class Group
    Public GroupName As String 
   public GroupVehicle As Vehicle 
End Class

Public Class Vehicle
   Public licenseNumber As String 
End Class


Public Class Run
   Shared Sub Main()
      Dim test As Run = new Run()
      test.DeserializeObject("UnrefObj.xml")
   End Sub

   Public Sub DeserializeObject(filename As String)
      ' Create an instance of the XmlSerializer class.
      Dim myMapping As XmlTypeMapping = _
      (new SoapReflectionImporter().ImportTypeMapping _
      (GetType(Group)))
      Dim mySerializer As XmlSerializer =  _
      new XmlSerializer(myMapping)

      AddHandler mySerializer.UnreferencedObject, _
      AddressOf Serializer_UnreferencedObject

      ' Reading the file requires an  XmlTextReader.
      Dim reader As XmlTextReader = _
      new XmlTextReader(filename)
      reader.ReadStartElement()

      ' Deserialize and cast the object.
      Dim myGroup As Group  
      myGroup = CType( mySerializer.Deserialize(reader), Group)
      reader.ReadEndElement()
      reader.Close()
   End Sub

   Private Sub Serializer_UnreferencedObject _
   (sender As object , e As UnreferencedObjectEventArgs)
      Console.WriteLine("UnreferencedObject:")
      Console.WriteLine("ID: " + e.UnreferencedId)
      Console.WriteLine("UnreferencedObject: " + e.UnreferencedObject)
      Dim myVehicle As Vehicle = CType(e.UnreferencedObject, Vehicle)
      Console.WriteLine("License: " + myVehicle.licenseNumber)
       End Sub
 End Class

' The XML document should contain this information:

'<wrapper>

'  <Group xmlns:xsi="http:'www.w3.org/2001/XMLSchema-instance" 
'xmlns:xsd="http:'www.w3.org/2001/XMLSchema" id="id1" 
'n1:GroupName=".NET" xmlns:n1="http:'www.cpandl.com">
'   </Group>

'<Vehicle id="id2" n1:type="Vehicle" 
'xmlns:n1="http:'www.w3.org/2001/XMLSchema-instance">
'    <licenseNumber xmlns:q1="http:'www.w3.org/2001/XMLSchema" 
'n1:type="q1:string">ABCD</licenseNumber>
'  </Vehicle>

'<Vehicle id="id3" n1:type="Vehicle" 
'xmlns:n1="http:'www.w3.org/2001/XMLSchema-instance">
'    <licenseNumber xmlns:q1="http:'www.w3.org/2001/XMLSchema" 
'n1:type="q1:string">1234</licenseNumber>
'  </Vehicle>

'</wrapper>



.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.

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