I have a question regarding wcf and json.

I have a wcf service that uses defaultOutgoingResponseFormat="Json" as a setting resulting in a clean Json based on generated DTO objects.

My question is: Is there a way I can dynamically remove the DataMember attribute so I can control to generated Json output. I want to remove the fields if they were not selected based on the ExcludeIncludeFieldList.

The version I'm using is 2.6.

Any suggestions are welcome.

Hi ch,

What do you mean when you say "...generated based on DTO objects"? Are these your own DTOs or LLBLGen entities?

If possible, please show us the relevant code involved in this scenario.

The DTO objects are classes generated based on a template. So they are used instead of the regular generated entities.

But the question would remain the same for both types of objects. (DTO and LLbl Entities)

Once you use them in WCF, the datacontractserializer will process all the properties that have a datamember attribute. What I want is to dynamically decide the ones I want in the resulting Json.

I know how to intercept it in the wcf pipeline but it seems a lot of code to just dynamically decide to use the DataMember attribute.

I need to decide myself if I want to serialize the property or not.

No idea how to control that, seems to me an issue related to the serializer used, not something we can help with as it's outside the scope of our framework. The attributes are static meta-data so you likely need to augment the serializer (subclassing or configuration, no idea though how to do that in this case) to use other sets of metadata than reflection and the attributes.

I agree, I was only hoping you guys already had some experience in this

ch wrote:

I agree, I was only hoping you guys already had some experience in this

No sorry

I finally found the solution. My returned Json from the Wcf service now only returns the fields that are set in the original fetched ExcludeIncludeFieldList. This way the returned Json is massively smaller

The core of the solution is to:

1. write your own IDispatchMessageFormatter and a custom DefaultContractResolver
2. add the ExcludeIncludeFieldsList as a property to the dto object because you need to access it from the contractresolver
3. update the web config to use your new IDispatchMessageFormatter

I have included the necessary code should some1 have the same problem I had.

<extensions>
      <behaviorExtensions>
        <add name="newtonsoftJsonBehavior" type="yournamespace.NewtonsoftJsonBehaviorExtension, yourtype" />
      </behaviorExtensions>
    </extensions>

<behavior name="ormsEndpointBehavior">
          <webHttp defaultOutgoingResponseFormat="Json" helpEnabled="true" defaultBodyStyle="Bare" faultExceptionEnabled="true"/>
          <newtonsoftJsonBehavior/>
        </behavior>

Thanks for sharing and I'm glad you found a solution! The thread is in the helpdesk forum btw, so no-one but us and you can see it. Do you want us to move the thread to a general forum so more people can see it?

Yes off course. Maybe someone will find it useful