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FaultContractAttribute Class

Specifies one or more SOAP faults that are returned when a service operation encounters processing errors.


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

[AttributeUsageAttribute(AttributeTargets.Method, AllowMultiple = true, Inherited = false)]
public sealed class FaultContractAttribute : Attribute

The FaultContractAttribute type exposes the following members.

Public methodSupported by Portable Class LibraryFaultContractAttributeInitializes a new instance of the FaultContractAttribute class.

Public propertySupported by Portable Class LibraryActionGets or sets the action of the SOAP fault message that is specified as part of the operation contract.
Public propertySupported by Portable Class LibraryDetailTypeGets the type of a serializable object that contains error information.
Public propertyHasProtectionLevelGets a value that indicates whether the SOAP fault message has a protection level assigned.
Public propertySupported by Portable Class LibraryNameGets or sets the name of the fault message in Web Services Description Language (WSDL).
Public propertySupported by Portable Class LibraryNamespaceGets or sets the namespace of the SOAP fault.
Public propertyProtectionLevelSpecifies the level of protection the SOAP fault requires from the binding.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)

Public methodSupported by Portable Class LibraryEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected methodSupported by Portable Class LibraryFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Portable Class LibraryGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodSupported by Portable Class LibraryGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodSupported by Portable Class LibraryMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by Portable Class LibraryToStringReturns a string that represents the current object. (Inherited from Object.)

Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)

Mark an operation with the FaultContractAttribute attribute to declare one or more specific exception conditions that are added to the Web Service Description Language (WSDL) description of the service operation as explicit SOAP fault messages returned by the operation.

In all managed applications, processing errors are represented by Exception objects. In SOAP-based applications such as applications, service methods communicate processing error information using SOAP fault messages. Because applications execute under both types of error systems, any managed exception information that must be sent to the client must be converted from exceptions into SOAP faults. You can use the default service exception behaviors, or you can explicitly control whether -- and how -- exceptions are mapped to fault messages. For an overview of exceptions and SOAP faults in applications, see Specifying and Handling Faults in Contracts and Services.

It is recommended that service operations use the FaultContractAttribute to formally specify all SOAP faults that a client can expect to receive in the normal course of an operation. It is also recommended that only that information a client must know is returned in a SOAP fault to minimize information disclosure.

  • The Action property controls the action of the fault message.

  • The DetailType property gets the type of the detail object serialized in the fault message.

  • The Name and Namespace properties control the name and namespace, respectively, of the fault message.

  • The HasProtectionLevel indicates whether the fault message has a protection level specified, and if so, the ProtectionLevel property controls that level of protection.

Caution noteCaution

If a fault message carries information that is sensitive or can lead to security problems, it is strongly recommended that the ProtectionLevel property be set.

For many scenarios setting ProtectionLevel to EncryptAndSign for fault messages is sufficient. For more details, see Understanding Protection Level.

To return a specified fault from an operation marked with FaultContractAttribute, throw a FaultException<TDetail> (where the type parameter is the serializable error information) when the managed exception occurs during the operation. client applications surface the SOAP fault as the same type as was thrown in the client implementation -- that is, as a FaultException<TDetail> (where the typeparameter is the serializable error information). The FaultContractAttribute can be used only to specify SOAP faults for two-way service operations and for asynchronous operation pairs; one-way operations do not support SOAP faults and therefore do not support FaultContractAttribute.


You can use any serializable type to convey error information. The only restriction in this version of is that types specified in a FaultContractAttribute must be serializable by the System.Runtime.Serialization.DataContractSerializer. For the serialization support the DataContractSerializer provides, see Data Contract Serializer.

For example, to specify that clients can expect a SOAP fault that contains an Int32, place that type parameter in the FaultContractAttribute on your service method.


The following code examples do not set the ProtectionLevel, Name, or Namespace properties.

int Divide(int arg1, int arg2);

Then, in your service method, throw a new FaultException<TDetail> where the type parameter is the type that contains the error information (in the above case, a Int32). For example:

throw new FaultException<int>(4);

The preceding example is very basic; almost any information can be passed using an System.Int32 code, so this detail type is not the most useful. Typically, applications specify SOAP faults with detail types specific to the error information requirements of the client. For a more complete example, see the Example section.


If you specify a FaultException<TDetail> where the type parameter is a System.String, the string value is assigned to the Detail property in the client application; clients cannot retrieve that string by calling the FaultException<TDetail>.ToString method. To have the string value returned when the client application calls Exception.ToString, throw a System.ServiceModel.FaultException exception inside the operation and pass the string to the constructor.

To explicitly control the behavior of the application when an exception or FaultException<TDetail> is thrown, implement the System.ServiceModel.Dispatcher.IErrorHandler interface on an System.ServiceModel.Description.IServiceBehavior, System.ServiceModel.Description.IContractBehavior or System.ServiceModel.Description.IEndpointBehavior and assign it to the ChannelDispatcherErrorhandlers() property. IErrorHandlerenables you to explicitly control the SOAP fault that is generated and whether to send it back to the client.

To facilitate debugging, set the ServiceBehaviorAttribute.IncludeExceptionDetailInFaults to true in code or you can use the ServiceDebugBehavior.IncludeExceptionDetailInFaults in an application configuration file. When enabled, the service automatically returns exception information to the caller. These faults appear to the client as FaultException exceptions.

Important noteImportant

Because managed exceptions can expose internal application information, setting ServiceBehaviorAttribute.IncludeExceptionDetailInFaults or ServiceDebugBehavior.IncludeExceptionDetailInFaults to true can permit clients to obtain information about internal service operation exceptions, including personally identifiable or other sensitive information.

Therefore, setting ServiceBehaviorAttribute.IncludeExceptionDetailInFaults or ServiceDebugBehavior.IncludeExceptionDetailInFaults to true is only recommended as a way of temporarily debugging a service application. In addition, the WSDL for a method that returns unhandled managed exceptions in this way does not contain the contract for the FaultException<TDetail> of type String. Clients must expect the possibility of an unknown SOAP fault (returned to clients as System.ServiceModel.FaultException objects) to obtain the debugging information properly.

The following code example shows the use of FaultContractAttribute to specify that the SampleMethod operation can return a SOAP fault with the detail type of GreetingFault.

using System;
using System.Collections.Generic;
using System.Net.Security;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace Microsoft.WCF.Documentation
  public interface ISampleService{
    string SampleMethod(string msg);

  public class GreetingFault
    private string report;

    public GreetingFault(string message)
    { = message;

    public string Message
      get { return; }
      set { = value; }

  class SampleService : ISampleService
  #region ISampleService Members

  public string  SampleMethod(string msg)
    Console.WriteLine("Client said: " + msg);
    // Generate intermittent error behavior.
    Random rnd = new Random(DateTime.Now.Millisecond);
    int test = rnd.Next(5);
    if (test % 2 != 0)
      return "The service greets you: " + msg; 
      throw new FaultException<GreetingFault>(new GreetingFault("A Greeting error occurred. You said: " + msg));


The following code example shows that clients of ISampleService experience this SOAP fault as a FaultException<TDetail> of type GreetingFault.

using System;
using System.ServiceModel;
using System.ServiceModel.Channels;
using Microsoft.WCF.Documentation;

public class Client
  public static void Main()
    // Picks up configuration from the config file.
    SampleServiceClient wcfClient = new SampleServiceClient();
      // Making calls.
      Console.WriteLine("Enter the greeting to send: ");
      string greeting = Console.ReadLine();
      Console.WriteLine("The service responded: " + wcfClient.SampleMethod(greeting));

      Console.WriteLine("Press ENTER to exit:");

      // Done with service. 
    catch (TimeoutException timeProblem)
      Console.WriteLine("The service operation timed out. " + timeProblem.Message);
    catch (FaultException<GreetingFault> greetingFault)
    catch (FaultException unknownFault)
      Console.WriteLine("An unknown exception was received. " + unknownFault.Message);
    catch (CommunicationException commProblem)
      Console.WriteLine("There was a communication problem. " + commProblem.Message + commProblem.StackTrace);

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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