How to parse a collection of unknown JSON object types inside a known JSON structure using JSON.Net?

Question

I am attempting to parse some JSON that has a known top level schema. However inside the schema is one JSON object that can contain various types of JSON objects.

Example

{
  "knownfield1": data,
  "knownfield2": data,
  "knownfieldcollection":
    {
       "fieldofunknowntype1": "string data",
       "fieldofunknowntype2": 
         {
           "subunknownfield1": "string data",
           "subunknownfield1": null
         },
       "fieldofunknowntype3": null
    }
}

I would like to make an object that contains a mapping of the known fields, but can read the unknown fields in dynamically. I was trying with Json.Net JToken and JObject, but I could not get it to work. I kept getting recursive JToken exceptions.

Any pointers on this would be great. Thank you.

Exception I am getting:

Type 'Newtonsoft.Json.Linq.JToken' is a recursive collection data 
contract which is not supported. Consider modifying the definition of 
collection 'Newtonsoft.Json.Linq.JToken' to remove references to itself.

--edit-- Mistyped Collection for object, fixed that.

What is the problem with JObject ? You can parse your json string using JObject.Parse. — Thomas, Apr 07 '16 at 00:47
I'm de-serializing the json into a C# object that has all the known fields defined. But for the life of me, I can't get the "knownfieldcollection" (object) to de-serialize if I use a property inside the C# object. I have tried `public JObject Field {get; set;}` and I get a recursion exception regarding JToken referencing itself. — Thaldin, Apr 07 '16 at 00:51
To use a JObject you have to parse the whole Json string. Could it be a solution ? Anyway you have a dynamic object.... — Thomas, Apr 07 '16 at 00:55
Yeah, that's what I am leaning towards, which will mean some refactoring, but hey, that's a developer's life right? =D heh — Thaldin, Apr 07 '16 at 00:56
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/108451/discussion-between-thomas-and-thaldin). — Thomas, Apr 07 '16 at 00:59
have a look http://stackoverflow.com/questions/16795045/accessing-all-items-in-the-jtoken-json-net — Thomas, Apr 07 '16 at 01:02
It looks like you are not actually using Json.NET to deserialize, you are using `DataContactJsonSerializer` and/or [tag:wcf]. See [Self Hosted WCF Rest service ERROR : Type 'Newtonsoft.Json.Linq.JToken' is a recursive collection data contract which is not supported](https://stackoverflow.com/questions/30759607), [How to have a WCF DataContract with a json dynamic member](https://stackoverflow.com/questions/12916865) and http://www.ikriv.com/blog/?p=1703. Can you create an [mcve](https://stackoverflow.com/help/mcve) of your problem showing how you deserialize your JSON? — dbc, Apr 07 '16 at 20:47

score 1 · Accepted Answer · answered Apr 08 '16 at 19:06

1

We have a winner. DBC hit the nail on the head. I had some left over WFC deserialization and it was causing problems. As soon I made sure all the DataContract code was completely cleared out and replaced everything with proper JSON.Net tags and calls, it worked wonderfully.

Thank you everyone for the support.

answered Apr 08 '16 at 19:06

Thaldin

283
3
15

This is not really an answer to the question. Please edit in the pertinent details so that this answer can stand by itself. – Lasse V. Karlsen Apr 08 '16 at 19:07
Not sure what you are looking for to be honest. JSON.Net parses as expected when I replaced some left WFC DataContractJsonDeserializer code with JSON.Net parsing code. As soon as I did, the JSON Object with the children of varying unknown types parsed into the object perfectly by simply using a Property of JObject type. – Thaldin Apr 08 '16 at 19:09

How to parse a collection of unknown JSON object types inside a known JSON structure using JSON.Net?

1 Answers1