I tried to serialize POCO class that was automatically generated from Entity Data Model .edmx and when I used
JsonConvert.SerializeObject
To serialize usin NEWTONSOFTJSON when you have loop issue, in my case I did not need modify global.asax or either apiconfig. I just use JsonSerializesSettings ignoring Looping handling.
JsonSerializerSettings jss = new JsonSerializerSettings();
jss.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
var lst = db.shCards.Where(m => m.CardID == id).ToList();
string json = JsonConvert.SerializeObject(lst, jss);