ISerializable 接口

允许对象控制其自己的序列化和反序列化过程。

**命名空间:**System.Runtime.Serialization
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
<ComVisibleAttribute(True)> _
Public Interface ISerializable
用法
Dim instance As ISerializable

[ComVisibleAttribute(true)] 
public interface ISerializable

[ComVisibleAttribute(true)] 
public interface class ISerializable

/** @attribute ComVisibleAttribute(true) */ 
public interface ISerializable

ComVisibleAttribute(true) 
public interface ISerializable

备注

任何可以序列化的类都必须用 SerializableAttribute 进行标记。如果某个类需要控制其序列化进程，它可以实现 ISerializable 接口。Formatter 在序列化时调用 GetObjectData，并使用表示对象所需的全部数据来填充所提供的 SerializationInfo。Formatter 使用图形中对象的类型来创建 SerializationInfo。需要自己发送代理的对象可以使用 SerializationInfo 上的 FullTypeName 和 AssemblyName 方法来更改所传输的信息。

在类继承的情况下，可以序列化从实现 ISerializable 的基类中派生的类。这种情况下，派生的类应在 GetObjectData 的实现内调用 GetObjectData 的基类实现。否则，不会序列化来自基类的数据。

ISerializable 接口表示带有 Constructor 签名（SerializationInfo 信息、StreamingContext 上下文）的构造函数。在反序列化时，仅在格式化程序已反序列化 SerializationInfo 中的数据后才调用当前构造函数。一般而言，如果该类未密封，则应保护此构造函数。

无法保证对象被反序列化的顺序。例如，如果一种类型引用尚未反序列化的类型，则会引发异常。如果创建具有这种依赖关系的类型，可以通过实现 IDeserializationCallback 接口和 OnDeserialization 方法来解决该问题。

序列化结构处理像处理扩展 Object 的类型一样，处理扩展 MarshalByRefObject 的对象类型。这些类型都可以使用 SerializableAttribute 来标记，并且可以将 ISerializable 接口实现为其他任何对象类型。它们的对象状态将被捕获并在流中持续。

当通过 System.Runtime.Remoting 使用这些类型时，远程处理结构会提供一个代理项，它将取代常用的序列化，而将代理序列化为 MarshalByRefObject。代理项是知道如何将特定类型的对象序列化和反序列化的帮助器。代理在大多数情况下对于用户不可见，其类型将是 ObjRef。

作为一种常规的设计模式，类很少会既使用可序列化属性来标记，又扩展 MarshalByRefObject。当组合这两项特性时，开发人员应仔细考虑可能的序列化和远程处理方案。MemoryStream 就是一个适用的示例。当 MemoryStream ( Stream ) 的基类从 MarshalByRefObject 扩展时，可以捕获 MemoryStream 的状态并随时将其还原。因此，这样做可能是有意义的：将该流的状态序列化到数据库中，并在稍后某一时间将其还原。但是，当通过远程处理来使用时，这种类型的对象将设置代理。

有关序列化 MarshalByRefObject 的派生类的更多信息，请参见 RemotingSurrogateSelector。有关如何实现 ISerializable 的更多信息，请参见 自定义序列化。

给实现者的说明 实现此接口，以允许对象参与其自己的序列化和反序列化过程。

示例

下面的代码示例演示如何使用 ISerializable 接口来定义类的自定义序列化行为。

Imports System
Imports System.Web
Imports System.IO
Imports System.Collections
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization
Imports System.Security.Permissions


' There should be only one instance of this type per AppDomain.
<Serializable()> _
Public NotInheritable Class Singleton
   Implements ISerializable

   ' This is the one instance of this type.
   Private Shared ReadOnly theOneObject As New Singleton

   ' Here are the instance fields.
   Public someString As String
   Public someNumber As Int32

   ' Private constructor allowing this type to construct the Singleton.
   Private Sub New()
      ' Do whatever is necessary to initialize the Singleton.
      someString = "This is a string field"
      someNumber = 123
   End Sub

   ' A method returning a reference to the Singleton.
   Public Shared Function GetSingleton() As Singleton
      Return theOneObject
   End Function

   ' A method called when serializing a Singleton.
   <SecurityPermissionAttribute(SecurityAction.LinkDemand, _
   Flags:=SecurityPermissionFlag.SerializationFormatter)> _
   Private Sub GetObjectData(ByVal info As SerializationInfo, _
      ByVal context As StreamingContext) _
      Implements ISerializable.GetObjectData

      ' Instead of serializing this object, we will  
      ' serialize a SingletonSerializationHelp instead.
      info.SetType(GetType(SingletonSerializationHelper))
      ' No other values need to be added.
   End Sub

   ' Note: ISerializable's special constructor is not necessary 
   ' because it is never called.
End Class


<Serializable()> _
Friend NotInheritable Class SingletonSerializationHelper
   Implements IObjectReference
   ' This object has no fields (although it could).

   ' GetRealObject is called after this object is deserialized.
   Public Function GetRealObject(ByVal context As StreamingContext) As Object Implements IObjectReference.GetRealObject
      ' When deserialiing this object, return a reference to 
      ' the Singleton object instead.
      Return Singleton.GetSingleton()
   End Function
End Class


Class App
   <STAThread()> Shared Sub Main()
        Run()
    End Sub

    Shared Sub Run()
        Dim fs As New FileStream("DataFile.dat", FileMode.Create)

        Try
            ' Construct a BinaryFormatter and use it 
            ' to serialize the data to the stream.
            Dim formatter As New BinaryFormatter

            ' Create an array with multiple elements refering to 
            ' the one Singleton object.
            Dim a1() As Singleton = {Singleton.GetSingleton(), Singleton.GetSingleton()}

            ' This displays "True".
            Console.WriteLine("Do both array elements refer to the same object? " & _
               Object.ReferenceEquals(a1(0), a1(1)))

            ' Serialize the array elements.
            formatter.Serialize(fs, a1)

            ' Deserialize the array elements.
            fs.Position = 0
            Dim a2() As Singleton = DirectCast(formatter.Deserialize(fs), Singleton())

            ' This displays "True".
            Console.WriteLine("Do both array elements refer to the same object? " & _
               Object.ReferenceEquals(a2(0), a2(1)))

            ' This displays "True".
            Console.WriteLine("Do all array elements refer to the same object? " & _
               Object.ReferenceEquals(a1(0), a2(0)))
        Catch e As SerializationException
            Console.WriteLine("Failed to serialize. Reason: " & e.Message)
            Throw
        Finally
            fs.Close()
        End Try

    End Sub
End Class

using System;
using System.Web;
using System.IO;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;
using System.Security.Permissions;


// There should be only one instance of this type per AppDomain.
[Serializable]
public sealed class Singleton : ISerializable 
{
    // This is the one instance of this type.
    private static readonly Singleton theOneObject = new Singleton();

    // Here are the instance fields.
    private string someString_value;
    private Int32 someNumber_value;

   public string SomeString
   {
       get{return someString_value;}
       set{someString_value = value;}
   }

   public Int32 SomeNumber
   {
       get{return someNumber_value;}
       set{someNumber_value = value;}
   }

    // Private constructor allowing this type to construct the Singleton.
    private Singleton() 
    { 
        // Do whatever is necessary to initialize the Singleton.
        someString_value = "This is a string field";
        someNumber_value = 123;
    }

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

    // A method called when serializing a Singleton.
    [SecurityPermissionAttribute(SecurityAction.LinkDemand, 
    Flags=SecurityPermissionFlag.SerializationFormatter)]
    void ISerializable.GetObjectData(
        SerializationInfo info, StreamingContext context) 
    {
        // Instead of serializing this object, 
        // serialize a SingletonSerializationHelp instead.
        info.SetType(typeof(SingletonSerializationHelper));
        // No other values need to be added.
    }

    // Note: ISerializable's special constructor is not necessary 
    // because it is never called.
}


[Serializable]
internal sealed class SingletonSerializationHelper : IObjectReference 
{
    // This object has no fields (although it could).

    // GetRealObject is called after this object is deserialized.
    public Object GetRealObject(StreamingContext context) 
    {
        // When deserialiing this object, return a reference to 
        // the Singleton object instead.
        return Singleton.GetSingleton();
    }
}


class App 
{
    [STAThread]
    static void Main() 
    {
        FileStream fs = new FileStream("DataFile.dat", FileMode.Create);

        try 
        {
            // Construct a BinaryFormatter and use it 
            // to serialize the data to the stream.
            BinaryFormatter formatter = new BinaryFormatter();

            // Create an array with multiple elements refering to 
            // the one Singleton object.
            Singleton[] a1 = { Singleton.GetSingleton(), Singleton.GetSingleton() };

            // This displays "True".
            Console.WriteLine(
                "Do both array elements refer to the same object? " + 
                (a1[0] == a1[1]));     

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

            // Deserialize the array elements.
            fs.Position = 0;
            Singleton[] a2 = (Singleton[]) formatter.Deserialize(fs);

            // This displays "True".
            Console.WriteLine("Do both array elements refer to the same object? " 
                + (a2[0] == a2[1])); 

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

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;
}

平台

Windows 98、Windows 2000 SP4、Windows Millennium Edition、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

ISerializable 成员
System.Runtime.Serialization 命名空间
RemotingSurrogateSelector 类

其他资源

XML 和 SOAP 序列化
自定义序列化