DataMemberAttribute Class

When applied to the member of a type, specifies that the member is part of a data contract and is serializable by the DataContractSerializer.

Namespace:  System.Runtime.Serialization
Assembly:  System.Runtime.Serialization (in System.Runtime.Serialization.dll)

<AttributeUsageAttribute(AttributeTargets.Property Or AttributeTargets.Field, Inherited := False,  _
	AllowMultiple := False)> _
Public NotInheritable Class DataMemberAttribute _
	Inherits Attribute
Dim instance As DataMemberAttribute

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.

Caution noteCaution:

You can apply the DataMemberAttribute to private fields or properties. Be aware that the data returned by the member (even if it private) will be serialized and deserialized, and thus can be viewed or intercepted by a malicious user or process.

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.


Properties to which the DataMemberAttribute attribute has been applied must have both get and set fields; they cannot be get-only or set-only.

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

The following example shows two types to which the DataContractAttribute and DataMemberAttribute attributes have been applied. The Name property is set to "Customer".

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 
            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
            Return extensionDataValue
        End Get 
            extensionDataValue = value
        End Set 
    End Property 
End Class  

Public Class Test
    Public Shared Sub Main(ByVal args() As String) 
        Catch exc As Exception
            Console.WriteLine("The serialization operation failed: {0} StackTrace: {1}", _
            exc.Message, exc.StackTrace)
            Console.WriteLine("Press <Enter> to exit....")
        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)
    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)
        Console.WriteLine(String.Format("{0} {1}, ID: {2}", _
        deserializedPerson.FirstName, deserializedPerson.LastName, deserializedPerson.IdNumber))
    End Sub  
End Class


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0
Was this page helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

© 2014 Microsoft