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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|AttributeTargets.Field, Inherited = false, 
	AllowMultiple = false)]
public sealed class DataMemberAttribute : Attribute

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".

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.
class Person : IExtensibleDataObject
    private string LastNameValue;
    // Apply the DataMemberAttribute to fields (or properties)  
    // that must be serialized.
    public string FirstName;

    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.
    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
            return extensionDatavalue;
            extensionDatavalue = value;

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

    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,
        DataContractSerializer ser =
            new DataContractSerializer(typeof(Person));
        ser.WriteObject(writer, p1);

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



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