DataMemberAttribute Class
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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


Initializes a new instance of the DataMemberAttribute class.


Gets or sets a value that specifies whether to serialize the default value for a field or property being serialized.


Gets whether P:System.Runtime.Serialization. DataMemberAttribute.Name has been explicitly set.


Gets or sets a value that instructs the serialization engine that the member must be present when reading or deserializing.


Gets or sets a data member name.


Gets or sets the order of serialization and deserialization of a member.


When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)


This API supports the product infrastructure and is not intended to be used directly from your code. Returns a value that indicates whether this instance is equal to a specified object.(Inherited from Attribute.)


Returns the hash code for this instance.(Inherited from Attribute.)


Gets the Type of the current instance.(Inherited from Object.)


When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.(Inherited from Attribute.)


When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)


Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)


Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from 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.


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.

Legacy Code Example

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.
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,


Universal Windows Platform
Available since 4.5
.NET Framework
Available since 3.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

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

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