Error adding Service Reference in VS2010 containing webHttp and wsHttp

Question

I'm creating a webservice with a wsHttp and JSON endpoint. The config below is hosted in a website project and works fine except when I try to create a service reference WITHIN the website. The endpoint behaviour seem to cause the error:

"Extension Error 'webHttp' cannot be added to this element. Verify the exception is registered in the extension collection at system.servicemode/extensions/behaviorExtensions"

It doesn't throw an error in svcUtil.exe. It seems VS specific but I'd like to get the bottom of it.

 <system.serviceModel>
    <behaviors>
      <endpointBehaviors>
        <behavior name="JSON">
          <webHttp />
        </behavior>
      </endpointBehaviors>
        <serviceBehaviors>
            <behavior name="HelloWorldBehavior">
                <serviceMetadata httpGetEnabled="true" />
                <serviceDebug includeExceptionDetailInFaults="false" />
            </behavior>
        </serviceBehaviors>
    </behaviors>
    <services>
        <service behaviorConfiguration="HelloWorldBehavior" name="HelloWorld">
          <endpoint address="/json" behaviorConfiguration="JSON"
            binding="webHttpBinding" contract="IHelloWorld" >
            </endpoint>
          <endpoint name="wcf"  address="" binding="wsHttpBinding"
          contract="IHelloWorld" />
            <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
        </service>
    </services>
</system.serviceModel>

Answer 1

I don't know whether it would solve your problem or not, but I think I should share my experience on a similar problem here.

I was getting an almost similar error:

Extension element 'webHttp' cannot be added to this element. Verify that the extension is registered in the extension collection at system.servicemodel/extensions/behaviorExtensions.

I tried a lot of things to fix this thing but couldn't do it. Then I found this suggestion on a similar problem from this page:

check your client (ASP.NET MVC) config and comment the WCF endpoint behavior which uses <enableWebScript />. Then add your service reference and uncomment the behavior. Same procedure has to be done if you want to update existing script reference. I guess it is a bug and should be reported to Microsoft Connect.

Mine wasn't ASP.NET MVC, but I tried the suggestion by commenting out

<behavior name="web">
          <webHttp />
        </behavior>

this portion from my app.config and could add the service reference then!! Then after adding the reference I just uncommented that portion again.

I can't explain it. It just worked for me and that's why I am sharing. Thanks.