Question

How do I format object ids and dates to show up correctly in the json serialized output using .net?

return Json(result, JsonRequestBehavior.AllowGet);

and here is the output that I get

{
  "_id": {
      o "Timestamp": 1321487136,
      o "Machine": 5156,
      o "Pid": -4604,
      o "Increment": 78,
      o "CreationTime": "/Date(1321487136000)/"
  },
"start": "/Date(1321487094000)/",
"end": "/Date(1638039600000)/",

}

I’d like the json to look like this

{
    "_id":"4e483da1e517801b09000004",
    "end":"2012-12-30T05:00:00.000Z",
    "start":"2011-08-14T17:26:57.000Z"
}

Reading through the advice below, got it working with the following

public class MongoSimpleIdConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return objectType == typeof(MongoDB.Bson.ObjectId);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            return new MongoDB.Bson.ObjectId((string)existingValue);
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            writer.WriteValue(((MongoDB.Bson.ObjectId)value).ToString());
        }
    }


 [HttpGet]
        public ContentResult Index()
        {

            var result = JsonConvert.SerializeObject(svc.GetTasks(), new MongoSimpleIdConverter(), new IsoDateTimeConverter());

            return new ContentResult { Content = result, ContentType = "application/json" };
        }

Answer 1

Huh, interesting, I was sure it was going to be a breeze, but it doesn’t seem like there’s a simple answer like “Write a converter and plug it with an attribute”.

I would recommend using a 3rd party like Json.net (which supports custom converters) and staying away from the built-in method.

I once wrote this code to handle the same problem with id serialization in the unofficial mongo driver –

public class OidConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(MongoDB.Oid);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        return new MongoDB.Oid((string)existingValue);
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        writer.WriteValue(((MongoDB.Oid)value).ToString());
    }
}