MessageContractAttribute Class
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MessageContractAttribute Class


Defines a strongly-typed class that corresponds to a SOAP message.

Namespace:   System.ServiceModel
Assembly:  System.ServiceModel (in System.ServiceModel.dll)


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


Initializes a new instance of the MessageContractAttribute class.


Gets a value that indicates whether the message has a protection level.


Gets or sets a value that specifies whether the message body has a wrapper element.


Gets or sets a value that specified whether the message must be encrypted, signed, or both.


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


Gets or sets the name of the wrapper element of the message body.


Gets or sets the namespace of the message body wrapper element.


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.)

Use the MessageContractAttribute attribute to specify the structure of the SOAP envelope for a particular message. Your service can then use the message as a parameter or return type in service operations. For information about controlling the serialization of the contents of a SOAP body without modifying the default SOAP envelope itself, see System.Runtime.Serialization.DataContractAttribute, Specifying Data Transfer in Service Contracts, and Using Data Contracts.


You cannot use custom message types in your service operation with regular serializable parameters. Either use custom message types or serializable parameters that are not Message objects. For details, see , Specifying Data Transfer in Service Contracts.

To implement a message contract for a type, annotate it with MessageContractAttribute and annotate one or more of the class's fields or properties with MessageBodyMemberAttribute, MessageHeaderAttribute, or MessageHeaderArrayAttribute.


System.ServiceModel.MessageParameterAttribute is not a message contract attribute and cannot be used in conjunction with MessageContractAttribute.

Use the Action and ReplyAction properties to specify the value of the <Action> element in the SOAP message.

  • Use the HasProtectionLevel and ProtectionLevel properties to indicate whether the SOAP message type has a protection level, and if so, what it is.

  • Use the IsWrapped property to indicate whether the message body has a wrapper element, and if so, use the WrapperName and WrapperNamespace properties to specify the name and namespace, respectively, of the wrapping element.

For more information, see Using Message Contracts.

The following code example shows the use of the MessageContractAttribute to control the SOAP envelope structure for both the request message and the response message, and the use of both the MessageHeaderAttribute (to create a SOAP header for the response message) and the MessageBodyMemberAttribute (to specify the bodies of both the request and response message). The code example contains an example of each message when sent.

using System;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Channels;

namespace Microsoft.WCF.Documentation
  [ServiceContract(Namespace = "Microsoft.WCF.Documentation")]
  interface IMessagingHello
     Action = "http://GreetingMessage/Action",
     ReplyAction = "http://HelloResponseMessage/Action"
    HelloResponseMessage Hello(HelloGreetingMessage msg);

  public class HelloResponseMessage
    private string localResponse = String.Empty;
    private string extra = String.Empty;

      Name = "ResponseToGreeting",
      Namespace = "")]
    public string Response
      get { return localResponse; }
      set { localResponse = value; }

      Name = "OutOfBandData",
      Namespace = "",
    public string ExtraValues
      get { return extra; }
      set { this.extra = value; }

    The following is the response message, edited for clarity.

        <a:Action s:mustUnderstand="1">http://HelloResponseMessage/Action</a:Action>
        <h:OutOfBandData s:mustUnderstand="1" xmlns:h="">Served by object 13804354.</h:OutOfBandData>
        <HelloResponseMessage xmlns="Microsoft.WCF.Documentation">
          <ResponseToGreeting xmlns="">Service received: Hello.</ResponseToGreeting>
  public class HelloGreetingMessage
    private string localGreeting;

      Name = "Salutations", 
      Namespace = ""
    public string Greeting
      get { return localGreeting; }
      set { localGreeting = value; }

   The following is the request message, edited for clarity.

        <!-- Note: Some header content has been removed for clarity.
        <a:To s:mustUnderstand="1"></a:To>
      <s:Body u:Id="_0" xmlns:u="">
        <HelloGreetingMessage xmlns="Microsoft.WCF.Documentation">
          <Salutations xmlns="">Hello.</Salutations>

  class MessagingHello : IMessagingHello
    public HelloResponseMessage Hello(HelloGreetingMessage msg)
      Console.WriteLine("Caller sent: " + msg.Greeting);
      HelloResponseMessage responseMsg = new HelloResponseMessage();
      responseMsg.Response = "Service received: " + msg.Greeting;
      responseMsg.ExtraValues = String.Format("Served by object {0}.", this.GetHashCode().ToString());
      Console.WriteLine("Returned response message.");
      return responseMsg;

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

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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