IDeserializationCallback Interface

 

Indicates that a class is to be notified when deserialization of the entire object graph has been completed. Note that this interface is not called when deserializing with the XmlSerializer (System.Xml.Serialization.XmlSerializer).

Namespace:   System.Runtime.Serialization
Assembly:  mscorlib (in mscorlib.dll)

<ComVisibleAttribute(True)>
Public Interface IDeserializationCallback

NameDescription
System_CAPS_pubmethodOnDeserialization(Object)

Runs when the entire object graph has been deserialized.

Notes to Implementers:

Implement the current interface as part of support for a method that is called when deserialization of the object graph is complete.

If an object needs to execute code on its child objects, it can delay this action, implement IDeserializationCallback, and execute the code only when it is called back on this interface.

Imports System
Imports System.IO
Imports System.Collections
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization

' This class is serializable and will have its OnDeserialization method
' called after each instance of this class is deserialized.
<Serializable()> Class Circle
   Implements IDeserializationCallback
   Private m_radius As Double

   ' To reduce the size of the serialization stream, the field below is 
   ' not serialized. This field is calculated when an object is constructed
   ' or after an instance of this class is deserialized.
   <NonSerialized()> Public m_area As Double

   Public Sub New(ByVal radius As Double)
      m_radius = radius
      m_area = Math.PI * radius * radius
   End Sub

   Private Sub OnDeserialization(ByVal sender As Object) _
      Implements IDeserializationCallback.OnDeserialization
      ' After being deserialized, initialize the m_area field 
      ' using the deserialized m_radius value.
      m_area = Math.PI * m_radius * m_radius
   End Sub

   Public Overrides Function ToString() As String
      Return String.Format("radius={0}, area={1}", m_radius, m_area)
   End Function
End Class


Class Class1
   <STAThread()> Shared Sub Main()
      Serialize()
      Deserialize()
   End Sub

   Shared Sub Serialize()
      Dim c As New Circle(10)
      Console.WriteLine("Object being serialized: " + c.ToString())

      ' To serialize the Circle, you must first open a stream for 
      ' writing. Use a file stream here.
      Dim fs As New FileStream("DataFile.dat", FileMode.Create)

      ' Construct a BinaryFormatter and use it 
      ' to serialize the data to the stream.
      Dim formatter As New BinaryFormatter
      Try
         formatter.Serialize(fs, c)
      Catch e As SerializationException
         Console.WriteLine("Failed to serialize. Reason: " + e.Message)
         Throw
      Finally
         fs.Close()
      End Try
   End Sub


   Shared Sub Deserialize()
      ' Declare the Circle reference
      Dim c As Circle = Nothing

      ' Open the file containing the data that you want to deserialize.
      Dim fs As New FileStream("DataFile.dat", FileMode.Open)
      Try
         Dim formatter As New BinaryFormatter

         ' Deserialize the Circle from the file and 
         ' assign the reference to the local variable.
         c = CType(formatter.Deserialize(fs), Circle)
      Catch e As SerializationException
         Console.WriteLine("Failed to deserialize. Reason: " + e.Message)
         Throw
      Finally
         fs.Close()
      End Try

      ' To prove that the Circle deserialized correctly, display its area.
      Console.WriteLine("Object being deserialized: " + c.ToString())
   End Sub
End Class

.NET Framework
Available since 1.1
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