DataMemberAttribute DataMemberAttribute DataMemberAttribute DataMemberAttribute Class

Definition

public ref class DataMemberAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Property, AllowMultiple=false, Inherited=false)]
[System.AttributeUsage(System.AttributeTargets.Property | System.AttributeTargets.Field, AllowMultiple=false, Inherited=false)]
public sealed class DataMemberAttribute : Attribute

type DataMemberAttribute = class
    inherit Attribute

Public NotInheritable Class DataMemberAttribute
Inherits Attribute

Inheritance

ObjectObjectObjectObject

AttributeAttributeAttributeAttribute

DataMemberAttributeDataMemberAttributeDataMemberAttributeDataMemberAttribute

Attributes

AttributeUsageAttribute AttributeUsageAttribute

Examples

The following example shows a type to which the DataContractAttribute and DataMemberAttribute attributes have been applied. The Name property on the DataMemberAttribute is set to "ID".

using System;
using System.Collections;
using System.IO;
using System.Runtime.Serialization;
using System.Xml;

// You must apply a DataContractAttribute or SerializableAttribute
// to a class to have it serialized by the DataContractSerializer.
[DataContract()]
class Person : IExtensibleDataObject
{
    private string LastNameValue;
    // Apply the DataMemberAttribute to fields (or properties) 
    // that must be serialized.
    [DataMember()]
    public string FirstName;

    [DataMember]
    public string LastName
    {
        get { return LastNameValue; }
        set { LastNameValue = value; }
    }

    [DataMember(Name = "ID")]
    public int IdNumber;

    // Note that you can apply the DataMemberAttribute to 
    // a private field as well.
    [DataMember]
    private string Secret;

    public Person(string newfName, string newLName, int newIdNumber)
    {
        FirstName = newfName;
        LastName = newLName;
        IdNumber = newIdNumber;
        Secret = newfName + newLName + newIdNumber;
    }

    // The extensionDataValue field holds data from future versions 
    // of the type.  This enables this type to be compatible with 
    // future versions. The field is required to implement the 
    // IExtensibleDataObject interface.

    private ExtensionDataObject extensionDatavalue;

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

public class Test
{
    public static void Main(string[] args)
    {
        try
        {
            WriteObject(@"DataMemberAttributeExample.xml");
            ReadObject(@"DataMemberAttributeExample.xml");
        }
        catch (Exception exc)
        {
            Console.WriteLine(
            "The serialization operation failed: {0} StackTrace: {1}",
            exc.Message, exc.StackTrace);
        }
        finally
        {
            Console.WriteLine("Press <Enter> to exit....");
            Console.ReadLine();
        }
    }

    public static void WriteObject(string filename)
    {
        // Create a new instance of the Person class.
        Person p1 = new Person("Zighetti", "Barbara", 101);
        FileStream writer = new FileStream(filename,
        FileMode.OpenOrCreate);
        DataContractSerializer ser =
            new DataContractSerializer(typeof(Person));
        ser.WriteObject(writer, p1);
        writer.Close();
    }

    public static void ReadObject(string filename)
    {
        // Deserialize an instance of the Person class 
        // from an XML file.
        FileStream fs = new FileStream(filename,
        FileMode.OpenOrCreate);
        DataContractSerializer ser =
            new DataContractSerializer(typeof(Person));
        // Deserialize the data and read it from the instance.
        Person deserializedPerson = (Person)ser.ReadObject(fs);
        fs.Close();
        Console.WriteLine(String.Format("{0} {1}, ID: {2}",
        deserializedPerson.FirstName, deserializedPerson.LastName,
        deserializedPerson.IdNumber));
    }

}

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

' You must apply a DataContractAttribute or SerializableAttribute
' to a class to have it serialized by the DataContractSerializer.
<DataContract()>  _
Class Person
    Implements IExtensibleDataObject

    Private LastNameValue As String
     
    ' Apply the DataMemberAttribute to fields (or properties) 
    ' that must be serialized.
    
    <DataMember()>  _
    Public FirstName As String
    
    <DataMember()>  _
    Public Property LastName() As String
        Get
            Return LastNameValue 
        End Get

        Set(ByVal Value As String)
           LastNameValue = Value
        End Set
    End Property

    
    <DataMember(Name:="ID")>  _
    Public IdNumber As Integer
    
    ' Note that you can apply the DataMemberAttribute to 
    ' a private field as well.
    <DataMember()>  _
    Private Secret As String
    
    Public Sub New(ByVal newfName As String, ByVal newLName As String, ByVal newIdNumber As Integer) 
        FirstName = newfName
        LastName = newLName
        IdNumber = newIdNumber
        Secret = newfName + newLName + newIdNumber.ToString()
    
    End Sub 
    
    ' The ExtensionData field holds data from future versions 
    ' of the type.  This enables this type to be compatible with 
    ' future versions. The field is required to implement the 
    ' IExtensibleObjectData interface.
    Private extensionDataValue As ExtensionDataObject
    
    Public Property ExtensionData() As ExtensionDataObject _
       Implements IExtensibleDataObject.ExtensionData
        Get
            Return extensionDataValue
        End Get
        Set
            extensionDataValue = value
        End Set
    End Property
End Class 

Public Class Test
    Public Shared Sub Main(ByVal args() As String) 
        Try
            ReadObject("DataMemberAttributeExample.xml")
            WriteObject("DataMemberAttributeExample.xml")
        Catch exc As Exception
            Console.WriteLine("The serialization operation failed: {0} StackTrace: {1}", _
            exc.Message, exc.StackTrace)
        Finally
            Console.WriteLine("Press <Enter> to exit....")
            Console.ReadLine()
        End Try
    End Sub 
    
    Public Shared Sub ReadObject(ByVal filename As String) 
        ' Create a new instance of the Person class.
        Dim p1 As New Person("Zighetti", "Barbara", 101)
        Dim writer As New FileStream(filename, FileMode.Create)
        Dim ser As New DataContractSerializer(GetType(Person))
        ser.WriteObject(writer, p1)
        writer.Close()
    End Sub 

    Public Shared Sub WriteObject(ByVal filename As String) 
        ' Deserialize an instance of the Person class 
        ' from an XML file.
        Dim fs As New FileStream(filename, FileMode.OpenOrCreate)
        Dim ser As New DataContractSerializer(getTYpe(Person))
        ' Deserialize the data and read it from the instance.
        Dim deserializedPerson As Person = ser.ReadObject(fs)
        fs.Close()
        Console.WriteLine(String.Format("{0} {1}, ID: {2}", _
        deserializedPerson.FirstName, deserializedPerson.LastName, deserializedPerson.IdNumber))
    End Sub 
End Class 

Remarks

Apply the DataMemberAttribute attribute in conjunction with the DataContractAttribute to identify members of a type that are part of a data contract. One of the serializers that can serialize data contracts is the DataContractSerializer.

The data contract model is an "opt-in" model. Applying the DataMemberAttribute to a field or property explicitly specifies that the member value will be serialized. In contrast, the BinaryFormatter serializes public and private fields of a type, and the XmlSerializer serializes only public fields and properties of a type.

By default, the CLR member name is used as the name of the data member. By setting the Name property, you can customize the name of the data member. This can be used to provide a name that may not be allowed as a CLR member name. When mapping to XML using the DataContractSerializer, this name is used as the name of the schema element in a type.

For more information about data contracts and data members, see Using Data Contracts. For more information about member names, see Data Member Default Values.

Constructors

Properties

Methods

Explicit Interface Implementations

Applies to

See Also

• DataContractAttribute
• DataContractSerializer
• IExtensibleDataObject