WCF Faults

See MSDN P&P Exception Management, MSDN Specifying and Handling Faults in Contracts and Services

FaultContract / FaultException

Add a [FaultContract(typeof(DivideByZeroException))] for types of faults that may be raised
Throw a untyped FaultException or
throw new FaultException<DivideByZeroException>(new DivideByZeroException());
- If you throw a faultException the service doesn't enter a faulted state
- you can also throw new FaultException<string>("Opps");

Client Exception Handling

You can't use using blocks with clients. Either use the above or write a partial class for the client with an explicit Dispose implementation (see below).

A WCF client can use faultException.Detail for a typed faultException.
Or: subscribe the client Faulted event.
Then rebuild the client (new Client())
client.Abort() as your client may throw on Close/Dispose when it is faulted

//don't do using for ClientBase
var client = new CalculatorClient();
try
{
    var result = client.Add(1, 10);
    //close can throw exceptions!
    //and will if(client.State == CommunicationState.Faulted)
    client.Close();
    total = result.Total;
}
//catch typed exceptions
catch (FaultException<DivideByZeroException> exception)
{
    var inner = exception.Detail;
    client.Abort();
    throw inner;
}
//catch untyped exception
catch (FaultException)
{
    client.Abort();
    throw;
}
//catch any other general error
catch (CommunicationException)
{
    client.Abort();
}
//catch a timeout (slow connection)
catch (TimeoutException)
{
    client.Abort();
}

Safe disposable client

Do a partial class. See also: Stack Overflow

public partial class Client : IDisposable
{
    void IDisposable.Dispose()
    {
        if (State == CommunicationState.Faulted)
        {
            Abort();
        }
        else
        {
            Close();
        }
    }
}

Normal exceptions

IncludeExceptionDetailInFaults="True". Actually it returns a FaultException(typeof(ExceptionDetail)) but does not use a wsdl FaultContract

ServiceContract code:

#if DEBUG
[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
#endif

Logging and handling exceptions: