Question

I have a service that may throw exceptions. I want to be able to catch the exceptions at the client. The main Exceptions I am interested in are DbUpdateException and InvalidOperationException. For the rest of the exceptions it is enough to know that an exception has been throws.

How can I have exceptions caught in the client?

Answer 1

If your WCF service throws an exception, then by default it will come to the client as a FaultException. You can configure your service to include exception details in faults, like so:

<serviceDebug includeExceptionDetailInFaults="true" />

But you probably don’t want to do this, it’s never a good idea to expose internal implementation details to clients.

If you want to distinguish between different service faults, you can create your own class, and register this as a fault that your service will throw. You can do this at the service contract level:

public interface YourServiceContract
{
   [FaultContract(typeof(YourFaultClass))]
   [OperationContract(...)]
   YourServiceResponseClass YourServiceOperation(YourServiceRequestClass request);
}

The class you use for your fault contract doesn’t have to implement anything (as you would have to do for a custom Exception), it will just get wrapped in a generic FaultContract object. You can then catch this in the client code like this:

try
{
   // service operation
}
catch (FaultException<YourFaultClass> customFault)
{
   ...
}
catch (FaultException generalFault)
{
   ...
}