ISerializable Interface

Definição

Permite que um objeto controle sua própria serialização e desserialização.Allows an object to control its own serialization and deserialization.

public interface class ISerializable
[System.Runtime.InteropServices.ComVisible(true)]
public interface ISerializable
type ISerializable = interface
Public Interface ISerializable
Derivado
Atributos

Exemplos

O exemplo de código a seguir demonstra o uso ISerializable da interface para definir o comportamento de serialização personalizado para uma classe.The following code example demonstrates the use of the ISerializable interface to define custom serialization behavior for a class.

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

ref class SingletonSerializationHelper;

// There should be only one instance of this type per AppDomain.

[Serializable]
public ref class Singleton sealed: public ISerializable
{
private:

   // This is the one instance of this type.
   static Singleton^ theOneObject = gcnew Singleton;

public:

   // Here are the instance fields.
   String^ someString;
   Int32 someNumber;

private:

   // Private constructor allowing this type to construct the singleton.
   Singleton()
   {
      
      // Do whatever is necessary to initialize the singleton.
      someString = "This is a String* field";
      someNumber = 123;
   }

public:

   // A method returning a reference to the singleton.
   static Singleton^ GetSingleton()
   {
      return theOneObject;
   }

   // A method called when serializing a Singleton.
   [System::Security::Permissions::SecurityPermissionAttribute
   (System::Security::Permissions::SecurityAction::LinkDemand, 
   Flags=System::Security::Permissions::SecurityPermissionFlag::SerializationFormatter)]
   virtual void GetObjectData( SerializationInfo^ info, StreamingContext context )
   {
      // Instead of serializing this Object*, we will  
      // serialize a SingletonSerializationHelp instead.
      info->SetType( SingletonSerializationHelper::typeid );

      // No other values need to be added.
   }

   // NOTE: ISerializable*'s special constructor is NOT necessary 
   // because it's never called
};

[Serializable]
private ref class SingletonSerializationHelper sealed: public IObjectReference
{
public:

   // This Object* has no fields (although it could).
   // GetRealObject is called after this Object* is deserialized
   virtual Object^ GetRealObject( StreamingContext context )
   {
      // When deserialiing this Object*, return a reference to 
      // the singleton Object* instead.
      return Singleton::GetSingleton();
   }
};

[STAThread]
int main()
{
   FileStream^ fs = gcnew FileStream( "DataFile.dat",FileMode::Create );
   try
   {
      // Construct a BinaryFormatter and use it 
      // to serialize the data to the stream.
      BinaryFormatter^ formatter = gcnew BinaryFormatter;

      // Create an array with multiple elements refering to 
      // the one Singleton Object*.
      array<Singleton^>^a1 = {Singleton::GetSingleton(),Singleton::GetSingleton()};

      // This displays S"True".
      Console::WriteLine( "Do both array elements refer to the same Object? {0}", (a1[ 0 ] == a1[ 1 ]) );

      // Serialize the array elements.
      formatter->Serialize( fs, a1 );

      // Deserialize the array elements.
      fs->Position = 0;
      array<Singleton^>^a2 = (array<Singleton^>^)formatter->Deserialize( fs );

      // This displays S"True".
      Console::WriteLine( "Do both array elements refer to the same Object? {0}", (a2[ 0 ] == a2[ 1 ]) );

      // This displays S"True".
      Console::WriteLine( "Do all  array elements refer to the same Object? {0}", (a1[ 0 ] == a2[ 0 ]) );
   }
   catch ( SerializationException^ e ) 
   {
      Console::WriteLine( "Failed to serialize. Reason: {0}", e->Message );
      throw;
   }
   finally
   {
      fs->Close();
   }

   return 0;
}
using System;
using System.Text;
using System.IO;
// Add references to Soap and Binary formatters.
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization.Formatters.Soap ;
using System.Runtime.Serialization;


[Serializable]
public class MyItemType : ISerializable
{
    public MyItemType()
    {
        // Empty constructor required to compile.
    }

    // The value to serialize.
    private string myProperty_value;

    public string MyProperty
    {
        get { return myProperty_value; }
        set { myProperty_value = value; }
    }
        
    // Implement this method to serialize data. The method is called 
    // on serialization.
    public void GetObjectData(SerializationInfo info, StreamingContext context)
    {
        // Use the AddValue method to specify serialized values.
        info.AddValue("props", myProperty_value, typeof(string));

    }

    // The special constructor is used to deserialize values.
    public MyItemType(SerializationInfo info, StreamingContext context)
    {
        // Reset the property value using the GetValue method.
        myProperty_value = (string) info.GetValue("props", typeof(string));
    }
}

// This is a console application. 
public static class Test
{
    static void Main()
    {
        // This is the name of the file holding the data. You can use any file extension you like.
        string fileName = "dataStuff.myData";

        // Use a BinaryFormatter or SoapFormatter.
        IFormatter formatter = new BinaryFormatter();
        //IFormatter formatter = new SoapFormatter();
            
        Test.SerializeItem(fileName, formatter); // Serialize an instance of the class.
        Test.DeserializeItem(fileName, formatter); // Deserialize the instance.
        Console.WriteLine("Done");
        Console.ReadLine();
    }

    public static void SerializeItem(string fileName, IFormatter formatter)
    {
        // Create an instance of the type and serialize it.
        MyItemType t = new MyItemType();
        t.MyProperty = "Hello World";

        FileStream s = new FileStream(fileName , FileMode.Create);
        formatter.Serialize(s, t);            
        s.Close();
    }


    public static void DeserializeItem(string fileName, IFormatter formatter)
    {
        FileStream s = new FileStream(fileName, FileMode.Open);
        MyItemType t = (MyItemType)formatter.Deserialize(s);
        Console.WriteLine(t.MyProperty);            
    }       
}
Imports System.Text
Imports System.IO

' Add references to Soap and Binary formatters.
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization.Formatters.Soap
Imports System.Runtime.Serialization


<Serializable()> _
Public Class MyItemType
    Implements ISerializable
    ' Empty constructor required to compile.
    Public Sub New()
    End Sub

    ' The value to serialize.
    Private myProperty_value As String

    Public Property MyProperty() As String
        Get
            Return myProperty_value
        End Get
        Set(value As String)
            myProperty_value = value
        End Set
    End Property

    ' Implement this method to serialize data. The method is called 
    ' on serialization.
    Public Sub GetObjectData(info As SerializationInfo, context As StreamingContext) Implements ISerializable.GetObjectData
        ' Use the AddValue method to specify serialized values.
        info.AddValue("props", myProperty_value, GetType(String))

    End Sub

    ' The special constructor is used to deserialize values.
    Public Sub New(info As SerializationInfo, context As StreamingContext)
        ' Reset the property value using the GetValue method.
        myProperty_value = DirectCast(info.GetValue("props", GetType(String)), String)
    End Sub
End Class

' This is a console application. 
Public Class Test


    Public Shared Sub Main()
        ' This is the name of the file holding the data. You can use any file extension you like.
        Dim fileName As String = "dataStuff.myData"

        ' Use a BinaryFormatter or SoapFormatter.
        Dim formatter As IFormatter = New BinaryFormatter()
        ' Dim formatter As IFormatter = New SoapFormatter()

        Test.SerializeItem(fileName, formatter)
        ' Serialize an instance of the class.
        Test.DeserializeItem(fileName, formatter)
        ' Deserialize the instance.
        Console.WriteLine("Done")
        Console.ReadLine()
    End Sub

    Public Shared Sub SerializeItem(fileName As String, formatter As IFormatter)
        ' Create an instance of the type and serialize it.
        Dim myType As New MyItemType()
        myType.MyProperty = "Hello World"

        Dim fs As New FileStream(fileName, FileMode.Create)
        formatter.Serialize(fs, myType)
        fs.Close()
    End Sub


    Public Shared Sub DeserializeItem(fileName As String, formatter As IFormatter)
        Dim fs As New FileStream(fileName, FileMode.Open)

        Dim myType As MyItemType = DirectCast(formatter.Deserialize(fs), MyItemType)
        Console.WriteLine(myType.MyProperty)
    End Sub
End Class

Comentários

Qualquer classe que possa ser serializada deve ser marcada com SerializableAttributeo.Any class that might be serialized must be marked with the SerializableAttribute. Se uma classe precisar controlar seu processo de serialização, ela poderá implementar a ISerializable interface.If a class needs to control its serialization process, it can implement the ISerializable interface. O Formatter chama o GetObjectData em tempo de serialização e popula o fornecido SerializationInfo com todos os dados necessários para representar o objeto.The Formatter calls the GetObjectData at serialization time and populates the supplied SerializationInfo with all the data required to represent the object. O Formatter cria um SerializationInfo com o tipo do objeto no grafo.The Formatter creates a SerializationInfo with the type of the object in the graph. Os objetos que precisam enviar proxies para si mesmos podem usar FullTypeName os AssemblyName métodos e SerializationInfo em para alterar as informações transmitidas.Objects that need to send proxies for themselves can use the FullTypeName and AssemblyName methods on SerializationInfo to change the transmitted information.

No caso da herança de classe, é possível serializar uma classe que deriva de uma classe base que implementa ISerializable.In the case of class inheritance, it is possible to serialize a class that derives from a base class that implements ISerializable. Nesse caso, a classe derivada deve chamar a implementação da classe base de GetObjectData dentro de sua implementação GetObjectDatade.In this case, the derived class should call the base class implementation of GetObjectData inside its implementation of GetObjectData. Caso contrário, os dados da classe base não serão serializados.Otherwise, the data from the base class will not be serialized.

A ISerializable interface implica um construtor com o construtor de assinaturaSerializationInfo (informações StreamingContext , contexto).The ISerializable interface implies a constructor with the signature constructor (SerializationInfo information, StreamingContext context). No momento da desserialização, o Construtor atual é chamado somente depois que os dados SerializationInfo no são desserializados pelo formatador.At deserialization time, the current constructor is called only after the data in the SerializationInfo has been deserialized by the formatter. Em geral, esse construtor deve ser protegido se a classe não estiver selada.In general, this constructor should be protected if the class is not sealed.

A ordem na qual os objetos são desserializados não pode ser garantida.The order in which objects are deserialized cannot be guaranteed. Por exemplo, se um tipo fizer referência a um tipo que ainda não foi desserializado, ocorrerá uma exceção.For example, if one type references a type that has not been deserialized yet, an exception will occur. Se você estiver criando tipos que têm essas dependências, poderá contornar o problema implementando a IDeserializationCallback interface e o OnDeserialization método.If you are creating types that have such dependencies, you can work around the problem by implementing the IDeserializationCallback interface and the OnDeserialization method.

A arquitetura de serialização manipula os tipos de MarshalByRefObject objeto que estendem o Objectmesmo que os tipos que se estendem.The serialization architecture handles object types that extend MarshalByRefObject the same as types that extend Object. Esses tipos podem ser marcados com o SerializableAttribute e implementar a ISerializable interface como qualquer outro tipo de objeto.These types can be marked with the SerializableAttribute and implement the ISerializable interface as any other object type. O estado do objeto será capturado e persistido no fluxo.Their object state will be captured and persisted onto the stream.

Quando esses tipos estão sendo usados por System.Runtime.Remotingmeio do, a infraestrutura de comunicação remota fornece um substituto que antecipa a serialização típica e, em vez MarshalByRefObjectdisso, serializa um proxy para o.When these types are being used through System.Runtime.Remoting, the remoting infrastructure provides a surrogate that preempts typical serialization and instead serializes a proxy to the MarshalByRefObject. Um substituto é um auxiliar que sabe como serializar e desserializar objetos de um tipo específico.A surrogate is a helper that knows how to serialize and deserialize objects of a particular type. O proxy, invisível para o usuário na maioria dos casos, será do tipo ObjRef.The proxy, invisible to the user in most cases, will be of type ObjRef.

Como um padrão de design geral, seria incomum que uma classe fosse marcada com o atributo serializável e estenda MarshalByRefObject.As a general design pattern, it would be unusual for a class to be both marked with the serializable attribute and extend MarshalByRefObject. Os desenvolvedores devem pensar atentamente sobre os cenários de serialização e comunicação remota possíveis ao combinar essas duas características.Developers should think carefully about the possible serialization and remoting scenarios when combining these two characteristics. Um exemplo em que isso pode ser aplicável é com MemoryStreamum.One example where this might be applicable is with a MemoryStream. Enquanto a classe base de MemoryStream (Stream) se estende MarshalByRefObjectde, é possível capturar o estado de um MemoryStream e restaurá-lo à medida que for.While the base class of MemoryStream (Stream) extends from MarshalByRefObject, it is possible to capture the state of a MemoryStream and restore it at will. Portanto, isso pode ser significativo para serializar o estado desse fluxo em um banco de dados e restaurá-lo em algum momento posterior.It might, therefore, be meaningful to serialize the state of this stream into a database and restore it at some later point in time. No entanto, quando usado por meio de comunicação remota, um objeto desse tipo seria proxy.However, when used through remoting, an object of this type would be proxied.

Para obter mais informações sobre a serialização de classes MarshalByRefObjectque se RemotingSurrogateSelectorestendem, consulte.For more information about serialization of classes that extend MarshalByRefObject, see RemotingSurrogateSelector. Para obter mais informações sobre ISerializablecomo implementar o, consulte Custom Serialization.For more information about implementing ISerializable, see Custom Serialization.

Notas aos Implementadores

Implemente essa interface para permitir que um objeto faça parte de sua própria serialização e desserialização.Implement this interface to allow an object to take part in its own serialization and deserialization.

Métodos

GetObjectData(SerializationInfo, StreamingContext)

Popula um SerializationInfo com os dados necessários para serializar o objeto de destino.Populates a SerializationInfo with the data needed to serialize the target object.

Aplica-se a

Veja também