ISerializable 介面

定義

允許物件控制它自己的序列化 (Serialization) 和還原序列化 (Deserialization)。Allows an object to control its own serialization and deserialization.

public interface class ISerializable
public interface ISerializable
[System.Runtime.InteropServices.ComVisible(true)]
public interface ISerializable
type ISerializable = interface
[<System.Runtime.InteropServices.ComVisible(true)>]
type ISerializable = interface
Public Interface ISerializable
衍生
屬性

範例

下列程式碼範例將示範如何使用 ISerializable 介面來定義類別的自訂序列化行為。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

備註

任何可能序列化的類別都必須以標記 SerializableAttributeAny class that might be serialized must be marked with the SerializableAttribute. 如果類別需要控制其序列化進程,它可以執行 ISerializable 介面。If a class needs to control its serialization process, it can implement the ISerializable interface. Formatter GetObjectData 在序列化期間呼叫,並以 SerializationInfo 表示物件所需的所有資料來擴展提供的。The Formatter calls the GetObjectData at serialization time and populates the supplied SerializationInfo with all the data required to represent the object. 會以 Formatter SerializationInfo 圖形中的物件類型建立。The Formatter creates a SerializationInfo with the type of the object in the graph. 需要自行傳送 proxy 的物件可以使用 FullTypeNameAssemblyName 方法 SerializationInfo 來變更傳送的資訊。Objects that need to send proxies for themselves can use the FullTypeName and AssemblyName methods on SerializationInfo to change the transmitted information.

在類別繼承的情況下,您可以將衍生自所執行基類的類別序列化 ISerializableIn the case of class inheritance, it is possible to serialize a class that derives from a base class that implements ISerializable. 在此情況下,衍生的類別應該在 GetObjectData 其執行的內部呼叫基類實作為 GetObjectDataIn this case, the derived class should call the base class implementation of GetObjectData inside its implementation of GetObjectData. 否則,將不會序列化來自基類的資料。Otherwise, the data from the base class will not be serialized.

介面意指具有簽章處理函式的函式 ISerializable SerializationInfo , (資訊、 StreamingContext 內容) 。The ISerializable interface implies a constructor with the signature constructor (SerializationInfo information, StreamingContext context). 在還原序列化時,只有在格式子還原序列化中的資料之後,才會呼叫目前的函式 SerializationInfoAt deserialization time, the current constructor is called only after the data in the SerializationInfo has been deserialized by the formatter. 一般而言,如果類別不是密封的,則應該保護此函式。In general, this constructor should be protected if the class is not sealed.

無法保證物件還原序列化的順序。The order in which objects are deserialized cannot be guaranteed. 例如,如果某個型別參考尚未還原序列化的型別,就會發生例外狀況。For example, if one type references a type that has not been deserialized yet, an exception will occur. 如果您要建立具有這類相依性的類型,您可以藉由執行介面和方法來解決此問題 IDeserializationCallback OnDeserializationIf you are creating types that have such dependencies, you can work around the problem by implementing the IDeserializationCallback interface and the OnDeserialization method.

序列化架構會處理擴充與擴充之 MarshalByRefObject 類型相同的物件類型 ObjectThe serialization architecture handles object types that extend MarshalByRefObject the same as types that extend Object. 這些類型可以用來標記 SerializableAttribute ,並將 ISerializable 介面實作為任何其他物件類型。These types can be marked with the SerializableAttribute and implement the ISerializable interface as any other object type. 其物件狀態將會被捕獲並保存到資料流程上。Their object state will be captured and persisted onto the stream.

當透過使用這些型別時 System.Runtime.Remoting ,遠端基礎結構會提供 shutdown 一般序列化的代理,並改為將 proxy 序列化為 MarshalByRefObjectWhen 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. 代理是一個 helper,知道如何序列化和還原序列化特定類型的物件。A surrogate is a helper that knows how to serialize and deserialize objects of a particular type. 在大部分情況下,使用者看不到的 proxy 將屬於類型 ObjRefThe proxy, invisible to the user in most cases, will be of type ObjRef.

一般的設計模式是,將類別標記為可序列化的屬性並進行擴充會是不尋常的 MarshalByRefObjectAs a general design pattern, it would be unusual for a class to be both marked with the serializable attribute and extend MarshalByRefObject. 開發人員應該在結合這兩個特性時,仔細考慮可能的序列化和遠端處理案例。Developers should think carefully about the possible serialization and remoting scenarios when combining these two characteristics. 其中一個可能適用的範例是使用 MemoryStreamOne example where this might be applicable is with a MemoryStream. 當 () 的基類 MemoryStream Stream 延伸時,就 MarshalByRefObject 可以捕獲的狀態, MemoryStream 並將它還原。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. 因此,它可能會有意義地將此資料流程的狀態序列化為資料庫,並在稍後的某個時間點還原。It might, therefore, be meaningful to serialize the state of this stream into a database and restore it at some later point in time. 不過,當透過遠端處理使用時,此類型的物件會是 proxy。However, when used through remoting, an object of this type would be proxied.

如需擴充之類別序列化的詳細資訊 MarshalByRefObject ,請參閱 RemotingSurrogateSelectorFor more information about serialization of classes that extend MarshalByRefObject, see RemotingSurrogateSelector. 如需有關如何執行的詳細資訊 ISerializable ,請參閱 自訂序列化For more information about implementing ISerializable, see Custom Serialization.

給實施者的注意事項

執行此介面可讓物件參與自己的序列化和還原序列化。Implement this interface to allow an object to take part in its own serialization and deserialization.

方法

GetObjectData(SerializationInfo, StreamingContext)

SerializationInfo 中填入序列化目標物件所需的資料。Populates a SerializationInfo with the data needed to serialize the target object.

適用於

另請參閱