Question

I’m hosting WCF as Widnows Service but I have a problem with handling Faulted state of WCF channel. Faulted event on ServiceHost never rise up.

Hosting application:

protected override void OnStart(string[] args)
    {
        _serviceHost = new ServiceHost(typeof(WCF_FaultTest.Service1));
        _serviceHost.Faulted += _serviceHost_Faulted;
        _serviceHost.Open();
    }

    void _serviceHost_Faulted(object sender, EventArgs e)
    {
        // never raise up..
    }

Faulted state I try to simulate like this:

    [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Single)]
public class Service1 : IService1
{
    public string GetFault()
    {
        throw new Exception("Should went to fault..");
    }

Do I using it correctly? Thank you.

Answer 1

You are using more than one CommunicationObject. When you throw the exception in your service implementation the channel is faulted, but the host it is not. The ServiceHost.Faulted event does not apply in this case.

One thing to remember is that once a CommunicationObject enters the faulted state, it can no longer be used. The only thing to do with a faulted CommunicationObject is to close/abort. After your service throws the exception, if you create a new channel you can still call the service. Therefore the service is not faulted.

From an architecture point of view, a service host event is not the “right” place to implement error handling. In general you want error processing to be part of the service configuration. For example error handling in a ServiceHost event doesn’t easily move to IIS hosting. Your comment makes it sound like IErrorHandler didn’t meet your requirements. What requirement are you trying to implement?