KnownTypeAttribute Kelas

Definisi

Ruang nama:

System.Runtime.Serialization

Rakitan:

System.Runtime.Serialization.Primitives.dll

Sumber:

KnownTypeAttribute.cs

Menentukan jenis yang harus dikenali oleh DataContractSerializer saat membuat serialisasi atau deserialisasi jenis tertentu.

public ref class KnownTypeAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Class | System.AttributeTargets.Struct, AllowMultiple=true, Inherited=true)]
public sealed class KnownTypeAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Class | System.AttributeTargets.Struct, AllowMultiple=true, Inherited=true)>]
type KnownTypeAttribute = class
    inherit Attribute

Public NotInheritable Class KnownTypeAttribute
Inherits Attribute

Warisan

Object

Attribute

KnownTypeAttribute

Atribut

AttributeUsageAttribute

Contoh

Contoh berikut menunjukkan jenis bernama Person dan jenis bernama IDInformation yang harus dikenali saat membuat serialisasi atau deserialisasi Person jenis.

using System;
using System.Collections.Generic;
using System.Collections;
using System.Text;
using System.IO;
using System.Runtime.Serialization;

namespace KnownTypeAttributeExample
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                Serialize("KnownTypeAttributeExample.xml");
                Deserialize("KnownTypeAttributeExample.xml");
                // Run this twice. The second time, comment out the
                // Serialize call and comment out the
                // KnownTypeAttribute on the Person class. The
                // deserialization will then fail.
            }
            catch (SerializationException exc)
            {
                Console.WriteLine("{0}: {1}", exc.Message,
                    exc.StackTrace);
            }
            finally
            {
                Console.WriteLine("Press Enter to exit...");
                Console.ReadLine();
            }
        }

        public static void Serialize(string path)
        {
            Person p = new Person();
            p.Miscellaneous.Add(DateTime.Now, "Hello");
            p.Miscellaneous.Add(DateTime.Now.AddSeconds(1), "World");
            IDInformation w = new IDInformation();
            w.ID = "1111 00000";
            p.Miscellaneous.Add(DateTime.Now.AddSeconds(2), w);
            DataContractSerializer ser =
                new DataContractSerializer(typeof(Person));
            FileStream fs = new FileStream(path, FileMode.Create);
            using (fs)
            {
                ser.WriteObject(fs, p);
            }
        }

        public static void Deserialize(string path)
        {
            DataContractSerializer ser =
                new DataContractSerializer(typeof(Person));
            FileStream fs = new FileStream(path, FileMode.Open);
            using (fs)
            {
                Person p2 = (Person)ser.ReadObject(fs);
                Console.WriteLine("Count {0}", p2.Miscellaneous.Count);
                foreach (DictionaryEntry de in p2.Miscellaneous)
                {
                    Console.WriteLine("Key {0} Value: {1}", de.Key,
                    de.Value);
                    if (de.Value.GetType() == typeof(IDInformation))
                    {
                        IDInformation www = (IDInformation)de.Value;
                        Console.WriteLine(
                        "\t Found ID Information. ID: {0} \n", www.ID);
                    }
                }
            }
        }

        // Apply the KnownTypeAttribute to the class that
        // includes a member that returns a Hashtable.
        [KnownType(typeof(IDInformation))]
        [DataContract]
        public class Person : IExtensibleDataObject
        {
            private ExtensionDataObject ExtensionDataObjectValue;

            public ExtensionDataObject ExtensionData
            {
                get { return ExtensionDataObjectValue; }
                set { ExtensionDataObjectValue = value; }
            }

            private Hashtable MiscellaneousValue = new Hashtable();
            [DataMember]
            public Hashtable Miscellaneous
            {
                get { return MiscellaneousValue; }
                set { MiscellaneousValue = value; }
            }
        }

        [DataContract]
        public class IDInformation : IExtensibleDataObject
        {
            private ExtensionDataObject ExtensionDataValue;
            public ExtensionDataObject ExtensionData
            {
                get { return ExtensionDataValue; }
                set { ExtensionDataValue = value; }
            }

            [DataMember]
            public string ID;
        }
    }
}

Imports System.Collections.Generic
Imports System.Collections
Imports System.Text
Imports System.IO
Imports System.Runtime.Serialization
Imports System.Xml

Class Program

    Shared Sub Main(ByVal args() As String)
        Try
            Serialize("KnownTypeAttributeExample.xml")
            Deserialize("KnownTypeAttributeExample.xml")
            ' Run this twice. The second time, comment out the
            ' Serialize call and comment out the 
            ' KnownTypeAttribute on the Person class. The
            ' deserialization will then fail.
        Catch exc As SerializationException
            Console.WriteLine("{0}: {1}", exc.Message, exc.StackTrace)
        Finally
            Console.WriteLine("Press Enter to exit...")
            Console.ReadLine()
        End Try

    End Sub


    Public Shared Sub Serialize(ByVal path As String)
        Dim p As New Person()
        p.Miscellaneous.Add(DateTime.Now, "Hello")
        p.Miscellaneous.Add(DateTime.Now.AddSeconds(1), "World")
        Dim w As New IDInformation()
        w.ID = "1111 00000"
        p.Miscellaneous.Add(DateTime.Now.AddSeconds(2), w)
        Dim ser As New DataContractserializer(GetType(Person))
        Using fs As New FileStream(path, FileMode.OpenOrCreate)
            ser.WriteObject(fs, p)
        End Using
    End Sub

    Public Shared Sub Deserialize(ByVal path As String)
        Dim ser As New DataContractserializer(GetType(Person))
        Using fs As New FileStream(path, FileMode.OpenOrCreate)
            Dim p2 As Person = ser.ReadObject(fs)
            Console.WriteLine("Count {0}", p2.Miscellaneous.Count)
            For Each de As DictionaryEntry In p2.Miscellaneous
                Console.WriteLine("Key {0} Value: {1}", de.Key, _
                de.Value)
                If TypeOf (de.Value) Is IDInformation Then
                    Dim www As IDInformation = de.Value
                    Console.WriteLine( _
                    "Found ID Information. ID: {0}", www.ID)
                End If
            Next
        End Using
    End Sub

    ' Apply the KnownTypeAttribute to the class that 
    ' includes a member that returns a Hashtable.
    <System.Runtime.Serialization.KnownType(GetType(IDInformation))> _
    <DataContract()> _
    Public Class Person
        Implements IExtensibleDataObject
        Private MiscellaneousValue As New Hashtable()
        Private ExtensionDataObjectValue As ExtensionDataObject

        Public Property ExtensionData() As ExtensionDataObject _
            Implements IExtensibleDataObject.ExtensionData
            Get
                Return ExtensionDataObjectValue
            End Get
            Set(ByVal value As ExtensionDataObject)
                ExtensionDataObjectValue = value
            End Set
        End Property

        <DataMember()> _
        Public Property Miscellaneous() As Hashtable
            Get
                Return MiscellaneousValue
            End Get
            Set(ByVal value As Hashtable)
                MiscellaneousValue = value
            End Set
        End Property
    End Class

    <DataContract()> _
    Public Class IDInformation
        Implements IExtensibleDataObject

        Private ExtensionDataObjectValue As ExtensionDataObject

        Public Property ExtensionData() As ExtensionDataObject _
            Implements IExtensibleDataObject.ExtensionData
            Get
                Return ExtensionDataObjectValue
            End Get

            Set(ByVal value As ExtensionDataObject)
                ExtensionDataObjectValue = value
            End Set
        End Property

        <DataMember()> _
        Public ID As String
    End Class
End Class

Keterangan

KnownTypeAttribute Terapkan atribut ke jenis untuk menunjukkan ke DataContractSerializer jenis yang harus dikenali saat membuat serialisasi atau deserialisasi instans jenis tempat atribut diterapkan. Atribut ini juga dapat dikenali oleh serializer lain yang memahami kontrak data.

Catatan

Dalam kode Anda, Anda dapat menggunakan kata KnownType alih-alih lebih lama KnownTypeAttribute.

Anda dapat menerapkan tepat satu KnownTypeAttribute instans dengan MethodName set properti, atau satu atau beberapa KnownTypeAttribute instans dengan Type set properti.

Konstruktor

KnownTypeAttribute(String)	Menginisialisasi instans KnownTypeAttribute baru kelas dengan nama metode yang mengembalikan jenis yang IEnumerable diketahui.
KnownTypeAttribute(Type)	Menginisialisasi instans KnownTypeAttribute baru kelas dengan jenis yang ditentukan.

Properti

MethodName	Mendapatkan nama metode yang akan mengembalikan daftar jenis yang harus dikenali selama serialisasi atau deserialisasi.
Type	Mendapatkan jenis yang harus dikenali selama serialisasi atau deserialisasi oleh DataContractSerializer.
TypeId	Ketika diimplementasikan di kelas turunan, mendapatkan pengidentifikasi unik untuk ini Attribute. (Diperoleh dari Attribute)

Metode

Equals(Object)	Mengembalikan nilai yang menunjukkan apakah instans ini sama dengan objek tertentu. (Diperoleh dari Attribute)
GetHashCode()	Mengembalikan kode hash untuk instans ini. (Diperoleh dari Attribute)
GetType()	Mendapatkan dari instans Type saat ini. (Diperoleh dari Object)
IsDefaultAttribute()	Ketika ditimpa di kelas turunan, menunjukkan apakah nilai instans ini adalah nilai default untuk kelas turunan. (Diperoleh dari Attribute)
Match(Object)	Saat ditimpa di kelas turunan, mengembalikan nilai yang menunjukkan apakah instans ini sama dengan objek tertentu. (Diperoleh dari Attribute)
MemberwiseClone()	Membuat salinan dangkal dari saat ini Object. (Diperoleh dari Object)
ToString()	Mengembalikan string yang mewakili objek saat ini. (Diperoleh dari Object)

Lihat juga

• DataContractAttribute
• DataMemberAttribute
• DataContractSerializer
• Jenis Kontrak Data yang Diketahui