在WCF服务通道调度程序上安装IErrorHandler

Question

I would like to install an implementation of IErrorHandler on a WCF service.

I am currently using this code, which does not seem to do anything:

logServiceHost = new ServiceHost(typeof(Logger));
logServiceHost.AddServiceEndpoint(typeof(ILogger), binding, address);

// Implementation of IErrorHandler.
var errorHandler = new ServiceErrorHandler();

logServiceHost.Open();

// Add error handler to all channel dispatchers.
foreach (ChannelDispatcher dispatcher in logServiceHost.ChannelDispatchers)
{
    dispatcher.ErrorHandlers.Add(errorHandler);
}

All code examples i've seen (including in the book i am using for WCF) shows how to install an error extension by using a custom created IServiceBehavior . Is this mandatory, or my approach should work as well?

Answer 1

Here is how I got this to work:

Create a class the implements IServiceBehavior. The service behavior will add your class that implements IErrorHandler:

public class GlobalExceptionHandlerBehavior : IServiceBehavior
{

    public void AddBindingParameters(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase, System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
    {
    }

    public void ApplyDispatchBehavior(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase)
    {
        foreach (ChannelDispatcherBase dispatcherBase in
             serviceHostBase.ChannelDispatchers)
        {
            var channelDispatcher = dispatcherBase as ChannelDispatcher;
            if (channelDispatcher != null)
                channelDispatcher.ErrorHandlers.Add(new ServiceErrorHandler());
        }

    }

    public void Validate(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase)
    {
    }
}

Insert the behavior when setting up your host befor calling .Open():

logServiceHost.Description.Behaviors.Insert(0, new GlobalExceptionHandlerBehavior());

You should then be able to put a break point inside your ErrorHandler() method within your ServiceErrorHandler class and it should break for you. This required no xml configuration and is completely code driven.

Answer 2

According to this article IErrorHandler instances are added via behaviors. There is no mention of any other mechanisms such as your example.

Answer 3

Phil, I believe Jay's answer follows the instructions on the MSDN link you've provided, he only has commented out the guts and kept the essential for this discussion. He then adds/registers the ServiceBehavior (and thus also the IErrorHandler) through his final line of code.

His answer is a solution to the posted question if you ask me. I've just validated it here in a minimal self hosted project.