create c# object from json array

Question

I am receiving an error when trying to convert my json array into an object.

I have a Json array with multiple layers like this :

    {  
   "error":"0",
   "result":{  
      "activities":{  
         "1":{  
            "activity_id":"15803",
            "activity_id_name":"Ashtanga vinyasa",
            "schedule":{  
               "1":{  
                  "available":"30",
                  "start":"09:00:00"
               }
            }
         },
         "2":{  
            "activity_id":"15804",
            "activity_id_name":"Yin/Yang",
            "schedule":{  
               "1":{  
                  "available":"30",
                  "start":"10:30:00"
               }
            }
         },
         "3":{  
            "activity_id":"15805",
            "activity_id_name":"Stress relief",
            "schedule":{  
               "1":{  
                  "available":"30",
                  "start":"20:00:00"
               }
            }
         }
      },
      "json_code":"2"
   },
   "id":null
}

From this i created an object that looks like this :

namespace LesRooster.Models
{
    public class JsonGroup
    {
        public string Error { get; set; }
        public List<Results> Result { get; set; }
        public string Id { get; set; }

    }

    public class Results
    {
        public Activities YogaActivities { get; set; }
        public int JsonCode { get; set; } 
    }

    public class Activities
    {
        public int ActivityId { get; set; }
        public string ActivityIdName { get; set; }
        public Schedule LesSchedule { get; set; }
    }

    public class Schedule
    {
        public int Available { get; set; }
        public DateTime Start { get; set; }
    }

}

When I try to add the array to the object with the following line :

JsonGroup jgroup = JsonConvert.DeserializeObject<JsonGroup>(JsonArrayCode);

I am receiving the following error :

Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[LesRooster.Models.Results]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.

Is there any way to resolve this? I would like to keep it as an object since it is easy to pass on in the view in my mvc5 application.

I have tried googling this but all solutions I have found are for single dimension json arrays.

The documentation of the API I request the json array from looks as follows :

json_code   integer 
Constant value: 2
activities  hash    
    {
    index : {
        activity_id: integer
        activity_id_name: string
        schedule: hash
        {
            index : {
                available: integer
                start: time
                }
            }
        }
}

The error is exactly what it says it is. In your JSON you have a property result that contains an object, with a property activities with a bunch more properties. That is not an array, so how is it supposed to deserialize it to one? You can either deserialize activities to a dictionary, or you can write your own converter to handle that property. — Matt Burland
– Matt Burland, Commented Sep 9, 2016 at 13:47
You don't have collections in JSON message but do have in DT object. — eocron
– eocron, Commented Sep 9, 2016 at 13:50

Raphaël Althaus · Accepted Answer · 2016-09-09 14:14:06Z

3

The structure of your classes does not match the structure of the JSON - this results in an exception. I have made some changes to your classes to reflect the JSON structure.

The main difference is that Activities is not an Array but a Dictionary.

namespace LesRooster.Models
{
    public class JsonGroup
    {
        public string Error { get; set; }
        public Result Result { get; set; }
        public string Id { get; set; }

    }

    public class Result {
        public IDictionary<string, Activities> Activities {get; set;}
        public int JsonCode {get; set;}
    }        

    public class Activities
    {
        [JsonProperty("activity_id")]
        public int ActivityId { get; set; }
        [JsonProperty("activity_id_name")]
        public string ActivityIdName { get; set; }
        public IDictionary<string, Schedule> Schedule { get; set; }
    }

    public class Schedule
    {
        public int Available { get; set; }
        public DateTime Start { get; set; }
    }    
}

edited Sep 9, 2016 at 14:14

Raphaël Althaus

60.6k6 gold badges106 silver badges127 bronze badges

answered Sep 9, 2016 at 13:59

Ralf Bönning

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6 Comments

Ňɏssa Pøngjǣrdenlarp Over a year ago

Schedule is a collection too

Ralf Bönning Over a year ago

@Plutonix: Thanx - rather it is a Dictionary as well. I will update my answer. I am just checking if DateTime for Start is the proper type.

Raphaël Althaus Over a year ago

Just think you need to put a [JsonProperty("activity_id_name")] on ActivityIdName property and [JsonProperty("activity_id")] on ActivityId property, or use something like this : migara.li/2016/01/09/json-net-easy-serialization

Niels Peeren Over a year ago

Thanks a bunch @rboe !! this did the trick, DateTime appears to be working so it should be the right type.

Raphaël Althaus Over a year ago

And your dictionaries could be of type <int, ...> (instead of string)

|

Not_A_SysAdmin · Accepted Answer · 2016-09-09 13:51:39Z

-1

Have you tried JSON.NET ? it's MIT licenced BTW.

answered Sep 9, 2016 at 13:51

Not_A_SysAdmin

1366 bronze badges

1 Comment

Johan Buret Over a year ago

This answer fails to adress the discrepancy between the code and the recieved JSON message.

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