DataContractAttribute Class


Specifies that the type defines or implements a data contract and is serializable by a serializer, such as the DataContractSerializer. To make their type serializable, type authors must define a data contract for their type.

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


[AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Enum, 
	Inherited = false, AllowMultiple = false)]
public sealed class DataContractAttribute : Attribute


Initializes a new instance of the DataContractAttribute class.


Gets whether Name has been explicitly set.


Gets whether Namespace has been explicitly set.


Gets or sets a value that indicates whether to preserve object reference data.


Gets whether IsReference has been explicitly set.


Gets or sets the name of the data contract for the type.


Gets or sets the namespace for the data contract for the type.


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 DataContractAttribute attribute to types (classes, structures, or enumerations) that are used in serialization and deserialization operations by the DataContractSerializer. If you send or receive messages by using the Windows Communication Foundation (WCF) infrastructure, you should also apply the DataContractAttribute to any classes that hold and manipulate data sent in messages. For more information about data contracts, see Using Data Contracts.

You must also apply the DataMemberAttribute to any field, property, or event that holds values you want to serialize. By applying the DataContractAttribute, you explicitly enable the DataContractSerializer to serialize and deserialize the data.


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

For more information about data contracts, see the topics listed in Using Data Contracts.

A data contract is an abstract description of a set of fields with a name and data type for each field. The data contract exists outside of any single implementation to allow services on different platforms to interoperate. As long as the data passed between the services conforms to the same contract, all the services can process the data. This processing is also known as a loosely coupled system. A data contract is also similar to an interface in that the contract specifies how data must be delivered so that it can be processed by an application. For example, the data contract may call for a data type named "Person" that has two text fields, named "FirstName" and "LastName". To create a data contract, apply the DataContractAttribute to the class and apply the DataMemberAttribute to any fields or properties that must be serialized. When serialized, the data conforms to the data contract that is implicitly built into the type.


A data contract differs significantly from an actual interface in its inheritance behavior. Interfaces are inherited by any derived types. When you apply the DataContractAttribute to a base class, the derived types do not inherit the attribute or the behavior. However, if a derived type has a data contract, the data members of the base class are serialized. However, you must apply the DataMemberAttribute to new members in a derived class to make them serializable.

If you are exchanging data with other services, you must describe the data contract. For the current version of the DataContractSerializer, an XML schema can be used to define data contracts. (Other forms of metadata/description could be used for the same purpose.) To create an XML schema from your application, use the ServiceModel Metadata Utility Tool (Svcutil.exe) with the /dconly command line option. When the input to the tool is an assembly, by default, the tool generates a set of XML schemas that define all the data contract types found in that assembly. Conversely, you can also use the Svcutil.exe tool to create Visual Basic or C# class definitions that conform to the requirements of XML schemas that use constructs that can be expressed by data contracts. In this case, the /dconly command line option is not required.

If the input to the Svcutil.exe tool is an XML schema, by default, the tool creates a set of classes. If you examine those classes, you find that the DataContractAttribute has been applied. You can use those classes to create a new application to process data that must be exchanged with other services.

You can also run the tool against an endpoint that returns a Web Services Description Language (WSDL) document to automatically generate the code and configuration to create an Windows Communication Foundation (WCF) client. The generated code includes types that are marked with the DataContractAttribute.

A data contract has two basic requirements: a stable name and a list of members. The stable name consists of the namespace uniform resource identifier (URI) and the local name of the contract. By default, when you apply the DataContractAttribute to a class, it uses the class name as the local name and the class's namespace (prefixed with "") as the namespace URI. You can override the defaults by setting the Name and Namespace properties. You can also change the namespace by applying the ContractNamespaceAttribute to the namespace. Use this capability when you have an existing type that processes data exactly as you require but has a different namespace and class name from the data contract. By overriding the default values, you can reuse your existing type and have the serialized data conform to the data contract.


In any code, you can use the word DataContract instead of the longer DataContractAttribute.

A data contract can also accommodate later versions of itself. That is, when a later version of the contract includes extra data, that data is stored and returned to a sender untouched. To do this, implement the IExtensibleDataObject interface.

For more information about versioning, see Data Contract Versioning.

The following example serializes and deserializes a class named Person to which the DataContractAttribute has been applied. Note that the Namespace and Name properties have been set to values that override the default settings.

namespace DataContractAttributeExample
    // Set the Name and Namespace properties to new values.
    [DataContract(Name = "Customer", Namespace = "")]
    class Person : IExtensibleDataObject
        // To implement the IExtensibleDataObject interface, you must also
        // implement the ExtensionData property.
        private ExtensionDataObject extensionDataObjectValue;
        public ExtensionDataObject ExtensionData
                return extensionDataObjectValue;
                extensionDataObjectValue = value;

        [DataMember(Name = "CustName")]
        internal string Name;

        [DataMember(Name = "CustID")]
        internal int ID;

        public Person(string newName, int newID)
            Name = newName;
            ID = newID;


    class Test
        public static void Main()
                Console.WriteLine("Press Enter to end");
            catch (SerializationException se)
                ("The serialization operation failed. Reason: {0}",

        public static void WriteObject(string path)
            // Create a new instance of the Person class and 
            // serialize it to an XML file.
            Person p1 = new Person("Mary", 1);
            // Create a new instance of a StreamWriter
            // to read and write the data.
            FileStream fs = new FileStream(path,
            XmlDictionaryWriter writer = XmlDictionaryWriter.CreateTextWriter(fs);
            DataContractSerializer ser =
                new DataContractSerializer(typeof(Person));
            ser.WriteObject(writer, p1);
            Console.WriteLine("Finished writing object.");
        public static void ReadObject(string path)
            // Deserialize an instance of the Person class 
            // from an XML file. First create an instance of the 
            // XmlDictionaryReader.
            FileStream fs = new FileStream(path, FileMode.OpenOrCreate);
            XmlDictionaryReader reader =
                XmlDictionaryReader.CreateTextReader(fs, new XmlDictionaryReaderQuotas());

            // Create the DataContractSerializer instance.
            DataContractSerializer ser =
                new DataContractSerializer(typeof(Person));

            // Deserialize the data and read it from the instance.
            Person newPerson = (Person)ser.ReadObject(reader);
            Console.WriteLine("Reading this object:");
            Console.WriteLine(String.Format("{0}, ID: {1}",
            newPerson.Name, newPerson.ID));


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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