Error while implementing IErrorHandler - Cannot add the behavior extension

Question

I was using these two articles as a reference to implement IErrorHandler:

ErrorHandler doesn't seem...

Roy Primrose's blog post

(I'm using .net Framework 3.5.)

However, I am having a bit trouble - whenever I try to start the service, I get following error:

System.Configuration.ConfigurationErrorsException: Cannot add the behavior extension 'errorHandlerExtension' to the service behavior named 'Test.TestService.Service1Behavior' because the underlying behavior type does not implement the IServiceBehavior interface.

Here are my code and config files:

ErrorhandlerExtension.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel.Configuration;
using System.Configuration;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;
using System.Collections.ObjectModel;

namespace Test.TestService
{
class ErrorHandlerExtension:BehaviorExtensionElement,IServiceBehavior
{
    public override Type BehaviorType
    {
        get { return typeof(ErrorHandler); }
    }
    protected override object CreateBehavior()
    {
        return new ErrorHandler();
    }
    void IServiceBehavior.AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters)
    {

    }
    private IErrorHandler GetInstance()
    {
        return new ErrorHandler();
    }
    void IServiceBehavior.ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {
        IErrorHandler errorHandlerInstance = GetInstance();
        foreach (ChannelDispatcher dispatcher in serviceHostBase.ChannelDispatchers)
        {
            dispatcher.ErrorHandlers.Add(errorHandlerInstance);
        }
    }

    void IServiceBehavior.Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {
        foreach (ServiceEndpoint endpoint in serviceDescription.Endpoints)
        {
            if (endpoint.Contract.Name.Equals("IMetadataExchange") &&
                endpoint.Contract.Namespace.Equals("http://schemas.microsoft.com/2006/04/mex"))
                continue;

            foreach (OperationDescription description in endpoint.Contract.Operations)
            {
                if (description.Faults.Count == 0)
                {
                    throw new InvalidOperationException("FaultContractAttribute not found on this method");
                }
            }
        }
    }

}

}

web.config:

<system.serviceModel>  
  <extensions>
      <behaviorExtensions>
        <add name="errorHandlerExtension"
          type="Test.TestService.ErrorHandlerExtension, Test.TestService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
      </behaviorExtensions>
    </extensions>

    <behaviors>
      <serviceBehaviors>
        <behavior name="Test.TestService.Service1Behavior">
          <serviceMetadata httpGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="true" />
          <errorHandlerExtension />
       </behavior>
     </serviceBehaviors>
    </behaviors>
</system.serviceModel>

Whenever I get rid of the errorHandlerExtension / element, the service works fine, but it fails to start whenever I include errorHandlerExtension element (with the error). I'm new to WCF and quite stumped. Any ideas?

edit: added ErrorHandler.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;
using System.Collections.ObjectModel;

namespace Test.TestService
{
public class ErrorHandler:IErrorHandler
{

    public bool HandleError(Exception error)
    {

        LogError("UnhandledError: "+ error);
        return true;
    }

    public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
    {
        FaultException faultException = new FaultException("Exception message:ProvideFault");
        MessageFault messageFault = faultException.CreateMessageFault();
        fault = Message.CreateMessage(version, messageFault, faultException.Action);
    }

}
}

Answer 1

Like I stated above, Implementing the IServiceBehavior in the ErrorHandler instead of ErrorHandlerExtension solved this problem.

Answer 2

I ran into the exact same issue. Turned out that I made a copy+paste error. Your problem - just as mine - can be also solved if BehaviorType would return typeof(ErrorHandlerExtension) and CreateBehavior would return with new ErrorHandlerExtension()