OnDeserializingAttribute OnDeserializingAttribute OnDeserializingAttribute OnDeserializingAttribute Class

Definition

Gibt bei Anwendung auf eine Methode an, dass die Methode während der Deserialisierung eines Objekts in einem Objektdiagramm aufgerufen wird.When applied to a method, specifies that the method is called during deserialization of an object in an object graph. Die Deserialisierungsreihenfolge relativ zu anderen Objekten im Diagramm ist nicht deterministisch.The order of deserialization relative to other objects in the graph is non-deterministic.

public ref class OnDeserializingAttribute sealed : Attribute
[System.AttributeUsage(System.AttributeTargets.Method, Inherited=false)]
[System.Runtime.InteropServices.ComVisible(true)]
public sealed class OnDeserializingAttribute : Attribute
type OnDeserializingAttribute = class
    inherit Attribute
Public NotInheritable Class OnDeserializingAttribute
Inherits Attribute
Vererbung
OnDeserializingAttributeOnDeserializingAttributeOnDeserializingAttributeOnDeserializingAttribute
Attribute

Beispiele

Im folgenden Beispiel werden die OnDeserializedAttributeAttribute OnSerializingAttribute, OnSerializedAttribute, und OnDeserializingAttribute auf Methoden in einer Klasse angewendet.The following example applies the OnDeserializedAttribute, OnSerializingAttribute, OnSerializedAttribute, and OnDeserializingAttribute attributes to methods in a class.

using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

public class Test
{
    public static void Main()
    {
        // Create a new TestSimpleObject object.
        TestSimpleObject obj = new TestSimpleObject();

        Console.WriteLine("\n Before serialization the object contains: ");
        obj.Print();

        // Open a file and serialize the object into binary format.
        Stream stream = File.Open("DataFile.dat", FileMode.Create);
        BinaryFormatter formatter = new BinaryFormatter();

        try
        {
            formatter.Serialize(stream, obj);

            // Print the object again to see the effect of the 
            //OnSerializedAttribute.
            Console.WriteLine("\n After serialization the object contains: ");
            obj.Print();

            // Set the original variable to null.
            obj = null;
            stream.Close();

            // Open the file "DataFile.dat" and deserialize the object from it.
            stream = File.Open("DataFile.dat", FileMode.Open);

            // Deserialize the object from the data file.
            obj = (TestSimpleObject)formatter.Deserialize(stream);

            Console.WriteLine("\n After deserialization the object contains: ");
            obj.Print();
            Console.ReadLine();
        }
        catch (SerializationException se)
        {
            Console.WriteLine("Failed to serialize. Reason: " + se.Message);
            throw;
        }
        catch (Exception exc)
        {
            Console.WriteLine("An exception occurred. Reason: " + exc.Message);
            throw;
        }
        finally
        {
            stream.Close();
            obj = null;
            formatter = null;
        }

    }
}


// This is the object that will be serialized and deserialized.
[Serializable()]
public class TestSimpleObject
{
    // This member is serialized and deserialized with no change.
    public int member1;

    // The value of this field is set and reset during and 
    // after serialization.
    private string member2;

    // This field is not serialized. The OnDeserializedAttribute 
    // is used to set the member value after serialization.
    [NonSerialized()]
    public string member3;

    // This field is set to null, but populated after deserialization.
    private string member4;

    // Constructor for the class.
    public TestSimpleObject()
    {
        member1 = 11;
        member2 = "Hello World!";
        member3 = "This is a nonserialized value";
        member4 = null;
    }

    public void Print()
    {
        Console.WriteLine("member1 = '{0}'", member1);
        Console.WriteLine("member2 = '{0}'", member2);
        Console.WriteLine("member3 = '{0}'", member3);
        Console.WriteLine("member4 = '{0}'", member4);
    }

    [OnSerializing()]
    internal void OnSerializingMethod(StreamingContext context)
    {
        member2 = "This value went into the data file during serialization.";
    }

    [OnSerialized()]
    internal void OnSerializedMethod(StreamingContext context)
    {
        member2 = "This value was reset after serialization.";
    }

    [OnDeserializing()]
    internal void OnDeserializingMethod(StreamingContext context)
    {
        member3 = "This value was set during deserialization";
    }

    [OnDeserialized()]
    internal void OnDeserializedMethod(StreamingContext context)
    {
        member4 = "This value was set after deserialization.";
    }
}

// Output:
//  Before serialization the object contains: 
// member1 = '11'
// member2 = 'Hello World!'
// member3 = 'This is a nonserialized value'
// member4 = ''
//
//  After serialization the object contains: 
// member1 = '11'
// member2 = 'This value was reset after serialization.'
// member3 = 'This is a nonserialized value'
// member4 = ''
//
//  After deserialization the object contains: 
// member1 = '11'
// member2 = 'This value went into the data file during serialization.'
// member3 = 'This value was set during deserialization'
// member4 = 'This value was set after deserialization.'
Imports System.IO
Imports System.Runtime.Serialization
Imports System.Runtime.Serialization.Formatters.Binary

Public Class Test
    Public Shared Sub Main()
        ' Create a new TestSimpleObject object.
        Dim obj As New TestSimpleObject()

        Console.WriteLine(vbLf + " Before serialization the object contains: ")
        obj.Print()

        ' Open a file and serialize the object into binary format.
        Dim stream As Stream = File.Open("DataFile.dat", FileMode.Create)
        Dim formatter As New BinaryFormatter()

        Try
            formatter.Serialize(stream, obj)

            ' Print the object again to see the effect of the 
            'OnSerializedAttribute.
            Console.WriteLine(vbLf + " After serialization the object contains: ")
            obj.Print()

            ' Set the original variable to null.
            obj = Nothing
            stream.Close()

            ' Open the file "DataFile.dat" and deserialize the object from it.
            stream = File.Open("DataFile.dat", FileMode.Open)

            ' Deserialize the object from the data file.
            obj = CType(formatter.Deserialize(stream), TestSimpleObject)

            Console.WriteLine(vbLf + " After deserialization the object contains: ")
            obj.Print()
            Console.ReadLine()
        Catch se As SerializationException
            Console.WriteLine("Failed to serialize. Reason: " + se.Message)
            Throw
        Catch exc As Exception
            Console.WriteLine("An exception occurred. Reason: " + exc.Message)
            Throw
        Finally
            stream.Close()
            obj = Nothing
            formatter = Nothing
        End Try
    End Sub
End Class


' This is the object that will be serialized and deserialized.
<Serializable()> _
Public Class TestSimpleObject
    ' This member is serialized and deserialized with no change.
    Public member1 As Integer

    ' The value of this field is set and reset during and 
    ' after serialization.
    Private member2 As String

    ' This field is not serialized. The OnDeserializedAttribute 
    ' is used to set the member value after serialization.
    <NonSerialized()> _
    Public member3 As String

    ' This field is set to null, but populated after deserialization.
    Private member4 As String

    ' Constructor for the class.
    Public Sub New()
        member1 = 11
        member2 = "Hello World!"
        member3 = "This is a nonserialized value"
        member4 = Nothing
    End Sub

    Public Sub Print()
        Console.WriteLine("member1 = '{0}'", member1)
        Console.WriteLine("member2 = '{0}'", member2)
        Console.WriteLine("member3 = '{0}'", member3)
        Console.WriteLine("member4 = '{0}'", member4)
    End Sub

    <OnSerializing()> _
    Friend Sub OnSerializingMethod(ByVal context As StreamingContext)
        member2 = "This value went into the data file during serialization."
    End Sub

    <OnSerialized()> _
    Friend Sub OnSerializedMethod(ByVal context As StreamingContext)
        member2 = "This value was reset after serialization."
    End Sub

    <OnDeserializing()> _
    Friend Sub OnDeserializingMethod(ByVal context As StreamingContext)
        member3 = "This value was set during deserialization"
    End Sub

    <OnDeserialized()> _
    Friend Sub OnDeserializedMethod(ByVal context As StreamingContext)
        member4 = "This value was set after deserialization."
    End Sub
End Class

' Output:
'  Before serialization the object contains: 
' member1 = '11'
' member2 = 'Hello World!'
' member3 = 'This is a nonserialized value'
' member4 = ''
'
'  After serialization the object contains: 
' member1 = '11'
' member2 = 'This value was reset after serialization.'
' member3 = 'This is a nonserialized value'
' member4 = ''
'
'  After deserialization the object contains: 
' member1 = '11'
' member2 = 'This value went into the data file during serialization.'
' member3 = 'This value was set during deserialization'
' member4 = 'This value was set after deserialization.'

Hinweise

Verwenden Sie OnDeserializingAttribute , um während der Deserialisierung Standardwerte festzulegen.Use the OnDeserializingAttribute to set default values during deserialization. Wenn der Typ, den Sie deserialisieren, z. b. keinen Konstruktor enthält, erstellen Sie eine-Methode, um Werte für beliebige Felder in der-Instanz festzulegen, und wenden Sie das-Attribut auf die-Methode an.For example, if the type that you are deserializing does not contain a constructor, create a method to set values of any fields in the instance and apply the attribute to the method.

Um das OnDeserializingAttributezu verwenden, muss die-Methode StreamingContext einen-Parameter enthalten.To use the OnDeserializingAttribute, the method must contain a StreamingContext parameter. Das-Attribut kennzeichnet die Methode, die von der Serialisierungsinfrastruktur aufgerufen werden soll, und StreamingContext stellt zusätzliche Daten über den Typ der Serialisierung bereit.The attribute marks the method to be called by the serialization infrastructure and the StreamingContext provides additional data about the type of serialization taking place. Die Verwendung wird im folgenden Code gezeigt:The usage is shown in the following code:

[OnDeserializing]
private void SetValuesOnDeserializing(StreamingContext context)
{
    // Code not shown.
}
<OnDeserializing()> _
Private Sub SetValuesOnDeserializing(ByVal context As StreamingContext)
    ' Code not shown.
End Sub

Hinweis

Sie können im Code das Wort OnDeserializing anstelle des längeren OnDeserializingAttribute verwenden.In your code, you can use the word OnDeserializing instead of the longer OnDeserializingAttribute.

Konstruktoren

OnDeserializingAttribute() OnDeserializingAttribute() OnDeserializingAttribute() OnDeserializingAttribute()

Initialisiert eine neue Instanz der OnDeserializingAttribute-Klasse.Initializes a new instance of the OnDeserializingAttribute class.

Methoden

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Gibt einen Wert zurück, der angibt, ob diese Instanz gleich einem angegebenen Objekt ist.Returns a value that indicates whether this instance is equal to a specified object.

(Inherited from Attribute)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Gibt den Hashcode für diese Instanz zurück.Returns the hash code for this instance.

(Inherited from Attribute)
GetType() GetType() GetType() GetType()

Ruft den Type der aktuellen Instanz ab.Gets the Type of the current instance.

(Inherited from Object)
IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute()

Gibt beim Überschreiben in einer abgeleiteten Klasse an, ob der Wert der Instanz der Standardwert für die abgeleitete Klasse ist.When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.

(Inherited from Attribute)
Match(Object) Match(Object) Match(Object) Match(Object)

Beim Überschreiben in einer abgeleiteten Klasse wird ein Wert zurückgegeben, der angibt, ob diese Instanz einem bestimmten Objekt entspricht.When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(Inherited from Attribute)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Erstellt eine flache Kopie des aktuellen Object.Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Gibt eine Zeichenfolge zurück, die das aktuelle Objekt darstellt.Returns a string that represents the current object.

(Inherited from Object)

Explizite Schnittstellenimplementierungen

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Ordnet eine Reihe von Namen einer entsprechenden Reihe von Dispatchbezeichnern zu.Maps a set of names to a corresponding set of dispatch identifiers.

(Inherited from Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Ruft die Typinformationen für ein Objekt ab, mit deren Hilfe die Typinformationen für eine Schnittstelle abgerufen werden können.Retrieves the type information for an object, which can be used to get the type information for an interface.

(Inherited from Attribute)
_Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32)

Ruft die Anzahl der Schnittstellen mit Typinformationen ab, die von einem Objekt bereitgestellt werden (0 oder 1).Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(Inherited from Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Stellt den Zugriff auf von einem Objekt verfügbar gemachte Eigenschaften und Methoden bereit.Provides access to properties and methods exposed by an object.

(Inherited from Attribute)

Eigenschaften

TypeId TypeId TypeId TypeId

Ruft bei Implementierung in einer abgeleiteten Klasse einen eindeutigen Bezeichner für dieses Attribute ab.When implemented in a derived class, gets a unique identifier for this Attribute.

(Inherited from Attribute)

Gilt für:

Siehe auch