KnownTypeAttribute 建構函式

定義

命名空間:

System.Runtime.Serialization

組件:

System.Runtime.Serialization.Primitives.dll

組件:

System.Runtime.Serialization.dll

組件:

netstandard.dll

初始化 KnownTypeAttribute 類別的新執行個體。

多載

KnownTypeAttribute(String)	使用負責傳回已知型別之 KnownTypeAttribute 的方法名稱，初始化 IEnumerable 類別的新執行個體。
KnownTypeAttribute(Type)	使用指定的型別來初始化 KnownTypeAttribute 類別的新執行個體。

KnownTypeAttribute(String)

使用負責傳回已知型別之 KnownTypeAttribute 的方法名稱，初始化 IEnumerable 類別的新執行個體。

public:
 KnownTypeAttribute(System::String ^ methodName);

public KnownTypeAttribute (string methodName);

new System.Runtime.Serialization.KnownTypeAttribute : string -> System.Runtime.Serialization.KnownTypeAttribute

Public Sub New (methodName As String)

參數

methodName

String

方法名稱，這個方法會傳回在序列化或還原序列化資料時所使用型別的 IEnumerable。

範例

下列範例會使用 methodName 參數來識別型別中的方法，而此型別包含了 Type 物件的陣列。

namespace KnownTypeAttributeExample
{
    using System;
    using System.Xml;
    using System.Collections.Generic;
    using System.Text;
    using System.Runtime.Serialization;
    using System.IO;
    // The constructor names the method that returns an array
    // of types that can be used during deserialization.
    [KnownTypeAttribute("KnownTypes")]
    [DataContract]
    public class Employee
    {
        public Employee(string newFName, string newLName)
        {
            FirstName = newFName;
            LastName = newLName;
        }
        [DataMember]
        internal string FirstName;
        [DataMember]
        internal string LastName;
        [DataMember]
        internal int id;
        [DataMember]
        internal Manager Boss;

        // This method returns the array of known types.
        static Type[] KnownTypes()
        {
            return new Type[]{typeof(Manager), typeof(Employee)};
        }
    }

    [DataContract]
    public class Manager : Employee
    {
        // Call the base class's constructor.
        public Manager(string newFName, string newLName)
            : base(newFName, newLName)
        { }

        [DataMember]
        internal Employee[] Reports;
    }

    class Program
    {
        public static void Main()
        {
            try
            {
                Serialize("person1.xml");
                Deserialize("person1.xml");
            }
            catch (SerializationException se)
            {
                Console.WriteLine("{0}: {1}",
                se.Message, se.StackTrace);
            }
            finally
            {
                Console.WriteLine("Press Enter to exit....");
                Console.ReadLine();
            }
        }

        static void Serialize(string path)
        {
            Employee emp = new Employee("John", "Peoples");
            emp.id = 3001;
            Manager theBoss = new Manager("Michiyo", "Sato");
            theBoss.id = 41;
            emp.Boss = theBoss;

            DataContractSerializer ser =
                new DataContractSerializer(typeof(Employee));

            FileStream fs =
                new FileStream(path, FileMode.OpenOrCreate);
            ser.WriteObject(fs, emp);
            fs.Close();
        }
        static void Deserialize(string path)
        {
            DataContractSerializer ser =
                new DataContractSerializer(typeof(Employee));
            FileStream fs = new FileStream(path,
            FileMode.Open);
            Employee p = (Employee)ser.ReadObject(fs);

            Console.WriteLine("{0} {1}, id:{2}", p.FirstName,
                p.LastName, p.id);
            fs.Close();
        }
    }
}

' The constructor names the method that returns an array 
' of types that can be used during deserialization.
<KnownTypeAttribute("KnownTypes"), DataContract()>  _
Public Class Employee
    Public Sub New(ByVal newFName As String, ByVal newLName As String) 
        FirstName = newFName
        LastName = newLName
    
    End Sub
    <DataMember()>  _
    Friend FirstName As String
    <DataMember()>  _
    Friend LastName As String
    <DataMember()>  _
    Friend id As Integer
    <DataMember()>  _
    Friend Boss As Manager
    
    ' This method returns the array of known types.
    Shared Function KnownTypes() As Type() 
        Return New Type() {GetType(Manager), GetType(Employee)}
    
    End Function 
End Class 

<DataContract()>  _
Public Class Manager
    Inherits Employee
    
    ' Call the base class's constructor.
    Public Sub New(ByVal newFName As String, ByVal newLName As String) 
        MyBase.New(newFName, newLName)
    
    End Sub 
    
    <DataMember()>  _
    Friend Reports() As Employee
End Class 

Class Program

    Public Shared Sub Main() 
        Try
            Serialize("person1.xml")
            Deserialize("person1.xml")
        Catch se As SerializationException
            Console.WriteLine("{0}: {1}", se.Message, se.StackTrace)
        Finally
            Console.WriteLine("Press Enter to exit....")
            Console.ReadLine()
        End Try
    
    End Sub 
    
    Shared Sub Serialize(ByVal path As String) 
        Dim emp As New Employee("John", "Peoples")
        emp.id = 3001
        Dim theBoss As New Manager("Michiyo", "Sato")
        theBoss.id = 41
        emp.Boss = theBoss

        Dim ser As New DataContractSerializer(GetType(Employee))
        
        Dim fs As New FileStream(path, FileMode.OpenOrCreate)
        ser.WriteObject(fs, emp)
        fs.Close()
    
    End Sub 
    
    Shared Sub Deserialize(ByVal path As String) 
        Dim ser As New DataContractSerializer(GetType(Employee))
        Dim fs As New FileStream(path, FileMode.Open)
        Dim p As Employee = CType(ser.ReadObject(fs), Employee)
        
        Console.WriteLine("{0} {1}, id:{2}", p.FirstName, p.LastName, p.id)
        fs.Close()
    
    End Sub 
End Class

備註

這個建構函式會使用符合類別方法的方法名稱。 此方法會傳回 IEnumerable<T> 物件的 Type。 在序列化或還原序列化期間，已套用該屬性的根型別內可以使用在集合中所找到的型別。

KnownTypeAttribute(Type)

使用指定的型別來初始化 KnownTypeAttribute 類別的新執行個體。

public:
 KnownTypeAttribute(Type ^ type);

public KnownTypeAttribute (Type type);

new System.Runtime.Serialization.KnownTypeAttribute : Type -> System.Runtime.Serialization.KnownTypeAttribute

Public Sub New (type As Type)

參數

type

Type

當序列化或還原序列化資料時，將包含做為已知型別的 Type。

範例

下列範例會示範應該要在還原序列化時加以包含的型別，即名稱 Person 和名稱 IDInformation 的型別。

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