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FaultException Class

Represents a SOAP fault.

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

public class FaultException : CommunicationException
/** @attribute SerializableAttribute() */ 
public class FaultException extends CommunicationException
public class FaultException extends CommunicationException
Not applicable.

In a service, use the FaultException class to create an untyped fault to return to the client for debugging purposes.

In a client, catch FaultException objects to handle unknown or generic faults, such as those returned by a service with the IncludeExceptionDetailInFaults property set to true. Because FaultException extends CommunicationException, remember to catch any FaultException objects prior to catching CommunicationException objects if you want to catch them separately.


Duplex services can also catch FaultException objects returned from their interaction with a duplex client.

In general, it is strongly recommended that you use the FaultContractAttribute to design your services to return strongly-typed SOAP faults (and not managed exception objects) for all fault cases in which you decide the client requires fault information. However, use the FaultException in the following situations:

  • To send SOAP faults from a service for debugging purposes.

  • To catch SOAP faults on a client when the faults are not part of the service contract.

Throw FaultException objects when you want the string to be passed to the constructor and retrieved by the client by calling the FaultException.ToString method. If you specify a fault contract of type System.ServiceModel.FaultException where the type parameter is System.String, the string value is available as the FaultException.Detail property and not by calling FaultException.ToString.

For details, see Handling Faults in Windows Communication Foundation Contracts.

The following code example shows the use of a try/catch block to catch and handle FaultException objects thrown from a service. This often occurs when debugging is turned on in the service application.

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 configuration 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:");
    catch (TimeoutException timeProblem)
      Console.WriteLine("The service operation timed out. " + timeProblem.Message);
    // Catch the contractually specified SOAP fault raised here as an exception.
    catch (FaultException<GreetingFault> greetingFault)
    // Catch unrecognized faults. This handler receives exceptions thrown by WCF
    // services when ServiceDebugBehavior.IncludeExceptionDetailInFaults 
    // is set to true.
    catch (FaultException faultEx)
      Console.WriteLine("An unknown exception was received. " 
        + faultEx.Message
        + faultEx.StackTrace
    // Standard communication fault handler.
    catch (CommunicationException commProblem)
      Console.WriteLine("There was a communication problem. " + commProblem.Message + commProblem.StackTrace);


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 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0
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