How do I deserialize a derived class with json.net

Question

I'm currently getting back the following json from a service that I do not own:

{
    "auc" : 320658953,
    "item" : 31294,
    "owner" : "Amacid",
    "ownerRealm" : "EarthenRing",
    "bid" : 289493,
    "buyout" : 371150,
    "quantity" : 1,
    "timeLeft" : "LONG",
    "rand" : 0,
    "seed" : 0,
    "context" : 0
}, {
    "auc" : 321175921,
    "item" : 82800,
    "owner" : "Drakonys",
    "ownerRealm" : "EarthenRing",
    "bid" : 7000384,
    "buyout" : 7507980,
    "quantity" : 1,
    "timeLeft" : "VERY_LONG",
    "rand" : 0,
    "seed" : 161297536,
    "context" : 0,
    "petSpeciesId" : 293,
    "petBreedId" : 9,
    "petLevel" : 1,
    "petQualityId" : 3
}, 

And I'm trying to deserialize it into proper CLR objects. It's obvious that these object hold a an object hierarchy on the server side; something like Item and PetItem : Item where PetItem has the extra 4 properties at the end there.

How do I handle this? I'm using Json.net to deserialize most of the other results from other services that are more consistent, but I'm looking for a strategy to handle situations like this. I've seen some solutions on how to have Json.net deserialize everything into an implied base class, but I'm not sure how to handle this upcasting type scenario

Answer 1

Here is yours example: http://dotnetbyexample.blogspot.ru/2012/02/json-deserialization-with-jsonnet-class.html?m=1

You just have to use overloaded method

JsonConvert.DeserializeObject<List<Item>>
  (r.EventArgs.Result, params Newtonsoft.Json.JsonConverter[] converters)

And write your converters

Answer 2

I don't see any alternative besides creating the class hierarchy in c# and then have some sort factory that checks for the presence of signature keys on the json side, creating the right c# object. petSpeciesId is probably a good candidate for distinguishing between Item and PetItem.

Ask yourself whether you really need to do this. Maybe a sparse class with unused properties will suit your purposes. Or just use System.Json.JsonObject to get an unordered key/value collection.

@Evgeny 's link to the blog post is a correct approach, but it does seem like an incredible amount of work! There's probably a simpler variation, but at bottom that's the work that needs to be done.