Program.X Program.X - 6 months ago 48
JSON Question

Serialize Entity Framework objects into JSON

It seems that serializing Entity Framework objects into JSON is not possible using either WCF's native DataContractJsonSerializer or ASP.NET's native JavaScript serializer. This is due to the reference counting issues both serializers reject. I have also tried Json.NET, which also fails specifically on a Reference Counting issue.




Edit: Json.NET can now serialize and deserialize Entity Framework entities.




My objects are Entity Framework objects, which are overloaded to perform additional business functionality (eg. authentication, etc.) and I do not want to decorate these classes with platform-specific attributes, etc. as I want to present a platform-agnostic API.

I've actually blogged about the individual steps I went though at http://bloggingabout.net/blogs/program.x/archive/2009/03/18/wcf-json-serialization-woes.aspx

Have I missed something obvious?

Answer

The way I do this is by projecting the data I want to serialize into an anonymous type and serializing that. This ensures that only the information I actually want in the JSON is serialized, and I don't inadvertently serialize something further down the object graph. It looks like this:

var records = from entity in context.Entities
              select new 
              {
                  Prop1 = entity.Prop1,
                  Prop2 = entity.Prop2,
                  ChildProp = entity.Child.Prop
              }
return Json(records);

I find anonymous types just about ideal for this. The JSON, obviously, doesn't care what type was used to produce it. And anonymous types give you complete flexibility as to what properties and structure you put into the JSON.