IDeserializationCallback Interface

Definition

Namespace:
System.Runtime.Serialization
Assembly:
System.Runtime.dll
Assembly:
System.Runtime.Serialization.Formatters.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll

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).

public interface class IDeserializationCallback
public interface IDeserializationCallback
[System.Runtime.InteropServices.ComVisible(true)]
public interface IDeserializationCallback
type IDeserializationCallback = interface
[<System.Runtime.InteropServices.ComVisible(true)>]
type IDeserializationCallback = interface
Public Interface IDeserializationCallback
Derived
Attributes
ComVisibleAttribute

Examples

using namespace System;
using namespace System::IO;
using namespace System::Collections;
using namespace System::Runtime::Serialization::Formatters::Binary;
using namespace System::Runtime::Serialization;

// This class is serializable and will have its OnDeserialization method
// called after each instance of this class is deserialized.

[Serializable]
ref class Circle: public IDeserializationCallback
{
private:
   Double m_radius;

public:

   // 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]
   Double m_area;
   Circle( Double radius )
   {
      m_radius = radius;
      m_area = Math::PI * radius * radius;
   }

   virtual void OnDeserialization( Object^ /*sender*/ )
   {
      // After being deserialized, initialize the m_area field 
      // using the deserialized m_radius value.
      m_area = Math::PI * m_radius * m_radius;
   }

   virtual String^ ToString() override
   {
      return String::Format( "radius= {0}, area= {1}", m_radius, m_area );
   }
};

void Serialize()
{
   Circle^ c = gcnew Circle( 10 );
   Console::WriteLine( "Object being serialized: {0}", c );

   // To serialize the Circle, you must first open a stream for 
   // writing. We will use a file stream here.
   FileStream^ fs = gcnew FileStream( "DataFile.dat",FileMode::Create );

   // Construct a BinaryFormatter and use it to serialize the data to the stream.
   BinaryFormatter^ formatter = gcnew BinaryFormatter;
   try
   {
      formatter->Serialize( fs, c );
   }
   catch ( SerializationException^ e ) 
   {
      Console::WriteLine( "Failed to serialize. Reason: {0}", e->Message );
      throw;
   }
   finally
   {
      fs->Close();
   }
}

void Deserialize()
{
   // Declare the Circle reference.
   Circle^ c = nullptr;

   // Open the file containing the data that we want to deserialize.
   FileStream^ fs = gcnew FileStream( "DataFile.dat",FileMode::Open );
   try
   {
      BinaryFormatter^ formatter = gcnew BinaryFormatter;

      // Deserialize the Circle from the file and 
      // assign the reference to our local variable.
      c = dynamic_cast<Circle^>(formatter->Deserialize( fs ));
   }
   catch ( SerializationException^ e ) 
   {
      Console::WriteLine( "Failed to deserialize. Reason: {0}", e->Message );
      throw;
   }
   finally
   {
      fs->Close();
   }

   // To prove that the Circle deserialized correctly, display its area.
   Console::WriteLine( "Object being deserialized: {0}", c );
}

[STAThread]
int main()
{
   Serialize();
   Deserialize();
}

using System;
using System.IO;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using 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 : IDeserializationCallback
{
    Double m_radius;

    // 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 Double m_area;

    public Circle(Double radius)
    {
        m_radius = radius;
        m_area = Math.PI * radius * radius;
    }

    void IDeserializationCallback.OnDeserialization(Object sender)
    {
        // After being deserialized, initialize the m_area field
        // using the deserialized m_radius value.
        m_area = Math.PI * m_radius * m_radius;
    }

    public override String ToString()
    {
        return String.Format("radius={0}, area={1}", m_radius, m_area);
    }
}

class Class1
{
    [STAThread]
    static void Main(string[] args)
    {
        Serialize();
        Deserialize();
    }

    static void Serialize()
    {
        Circle c = 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.
        FileStream fs = new FileStream("DataFile.dat", FileMode.Create);

        // Construct a BinaryFormatter and use it
        // to serialize the data to the stream.
        BinaryFormatter formatter = new BinaryFormatter();
        try
        {
            formatter.Serialize(fs, c);
        }
        catch (SerializationException e)
        {
            Console.WriteLine("Failed to serialize. Reason: " + e.Message);
            throw;
        }
        finally
        {
            fs.Close();
        }
    }

    static void Deserialize()
    {
        // Declare the Circle reference.
        Circle c = null;

        // Open the file containing the data that you want to deserialize.
        FileStream fs = new FileStream("DataFile.dat", FileMode.Open);
        try
        {
            BinaryFormatter formatter = new BinaryFormatter();

            // Deserialize the Circle from the file and
            // assign the reference to the local variable.
            c = (Circle) formatter.Deserialize(fs);
        }
        catch (SerializationException e)
        {
            Console.WriteLine("Failed to deserialize. Reason: " + e.Message);
            throw;
        }
        finally
        {
            fs.Close();
        }

        // To prove that the Circle deserialized correctly, display its area.
        Console.WriteLine("Object being deserialized: " + c.ToString());
    }
}

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

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.

Methods

OnDeserialization(Object)

Runs when the entire object graph has been deserialized.

Applies to

See also