Deserialize from json where can be single T object or array of T into List

Question

I have the code like this:

var json = GetJsonData(path);
JObject event_dates_data = JObject.Parse(json);
var event_dates_list = JObject.Parse(event_dates_data["document"]["date"].ToString());
var event_dates = JsonConvert.DeserializeObject<List<EventDate>>(event_dates_list.ToString());

Json may contains an array objects (for example "date:[{},{},{}]") or only one (for example "date:{}")

Json looks like that:

{
"document": {
"result": "success",
"resultcode": "000000",
"note": null,
"totaldates": "1",
"date": {
  "date_id": "351314",
  "live": "n",
  "datestart": "2012-03-07",
  "dateend": "2015-03-07",
  "timestart": "12:00",
  "timeend": "14:00",
  "date_available": "10000"
}
}
}

Or:

{
"document": {
"result": "success",
"resultcode": "000000",
"note": null,
"totaldates": "4",
"date": [
  {
    "date_id": "346022",
    "live": "n",
    "datestart": "2011-02-19",
    "dateend": "2011-02-19",
    "timestart": "12:00",
    "timeend": "14:00",
    "date_available": "10000"
  },
  {
    "date_id": "346023",
    "live": "n",
    "datestart": "2011-02-20",
    "dateend": "2011-02-20",
    "timestart": "12:00",
    "timeend": "14:00",
    "date_available": "10000"
  },
  {
    "date_id": "346024",
    "live": "n",
    "datestart": "2011-02-21",
    "dateend": "2011-02-21",
    "timestart": "12:00",
    "timeend": "14:00",
    "date_available": "10000"
  },
  {
    "date_id": "546580",
    "live": "y",
    "datestart": "2015-08-15",
    "dateend": "2015-08-15",
    "timestart": "12:00",
    "timeend": "14:00",
    "date_available": "10000"
  }
]
}
}

I have the poco for the "date":

public class EventDate {

    [JsonProperty("date_id")]
    public string Id { get; set; }


    [JsonProperty("live")]
    [JsonConverter(typeof(AvailableForSalesFiledConverter))]
    public bool AvailableForSales { get; set; }


    [JsonProperty("datestart")]
    public string DateStart { get; set; }


    [JsonProperty("dateend")]
    public string DateEnd { get; set; }


    [JsonProperty("timestart")]
    public string TimeStart { get; set; }


    [JsonProperty("timeend")]
    public string TimeEnd { get; set; }


    [JsonProperty("date_available")]
    public int DateAvailable { get; set; }
}

So when I'm trying to deserialize I getting exception: "Cannot deserialize the current JSON object (e.g. {\"name\":\"value\"}) into type 'System.Collections.Generic.List`1[TicketProvider.BrownPaperTickets.Entities.EventDate]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.\r\nTo fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.\r\nPath 'date_id', line 2, position 13." How can I get it to List?

brz · Answer 1 · 2014-08-30T12:21:18.777

1

var json = GetJsonData(path);
JObject event_dates_data = JObject.Parse(json);
var event_dates_list = JObject.Parse(event_dates_data["document"]["date"].ToString());
event_dates_list = string.Format("[{0}]", event_dates_list.Trim('[', ']'));
var event_dates = JsonConvert.DeserializeObject<List<EventDate>>(event_dates_list.ToString());

edited Aug 30 '14 at 12:21

answered Aug 30 '14 at 12:13

brz

5,926
1
18
18

Sure.. It works. But I suppose there are should be some standart ways from the Json.Net library. – Vitach Aug 30 '14 at 12:50
3

Using a `JsonConverter` is a much better solution than manually manipulating the JSON and reparsing it. See the linked duplicate question and answer. – Brian Rogers Aug 30 '14 at 14:53

Noctis · Answer 2 · 2014-08-30T12:02:06.280

I'm a bit puzzled since it seems you're doing a mishmash of things in there.

I would suggest you create a POCO object that represents your data as a class. It should have a list of type DateTime, and one of EventDate, and when you serialize, you simply serialize the entire class as:

var my_poco = // create your object here;
var poco_as_json = Newtonsoft.Json.JsonConvert.SerializeObject(my_poco);

// You then save that to a file (I assume that's what you're doing)

// Get it back will look like: 
var back_from_json = Newtonsoft.Json.JsonConvert
                                    .DeserializeObject<your_poco_class>(json);

// and then simply use the object's lists:
var dates  = back_from_json.event_dates_list; // list of dates
var events = = back_from_json.events;         // list of events?

Your poco is for the event date only.
You need another poco with variables for the rest:

"document", "result", "resultcode", "note", "totaldates", "date"

It'll probably be called document, totaldates will be an int, and date will be a List<DateEvent>.
That's what you'll serialize and deserialize.

Thank you for the answer. I edited my post please review it again. — Vitach, Aug 30 '14 at 11:39

score -2 · Answer 3 · answered Aug 30 '14 at 08:55

-2

First of all in your class convert the instance of the class in RootObject to the list for example:

class RootObject
{
public List<Class1> Property1 { get; set; }
}

Now you can access the items in that class as list.

answered Aug 30 '14 at 08:55

Bilal Amjad

149
3
11

1

You missed the point of the question-- sometimes the property is an array and sometimes it is a single object. If you declare it as a list, it will not work when the JSON has a single object, and vice versa. There is more to the solution than just changing the class declaration (although that is part of it). – Brian Rogers Aug 30 '14 at 14:42

Deserialize from json where can be single T object or array of T into List

3 Answers3

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