How to convert json array of values to nested json objects in C#

Question

I have a JSON file and one of the values is represented as a list of integers, but I would like to convert the list to nested JSONS with its value and surrogate key (autoincrement from 1 for each list).

Is it possible to use Newtonsoft.json.dll for this task?

This is actual example

{   
"content": {
    "table": [
        {
            "name": {
                "en": "questionnaire"
            },
            "data": [
                "154",
                "124254",
                "87575"             
            ]
        }           
      ]
    }
}

This is needed output:

{
"content": {
    "table": [
        {
            "name": {
                "en": "questionnaire"
            },
            "data": [
                {
                    "id": "1",
                    "value": "154"
                },
                {
                    "id": "2",
                    "value": "124254"
                },
                {
                    "id": "3",
                    "value": "87575"
                }
            ]
        }
      ]
    }
}

Thank you very much for any ideas.

Answer 1

You can create a custom converter which is responsible for converting data array into a new dictionary<string, string>. The custom converter looks like below:

public class DataConverter : JsonConverter
{
    private int _index = 1;
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        JToken token = JToken.FromObject(value);
        token.WriteTo(writer);

    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        JToken token = JToken.Load(reader);
        Dictionary<string, string> dict = new Dictionary<string, string>();
        try
        {
            foreach (var item in token)
            {
                dict.Add(_index++.ToString(),  item.ToString());//Filling the data to dictionary
            }
        }
        catch
        {
            // ignored
        }

        _index = 1;//Resetting index
        return dict;

    }

    public override bool CanConvert(Type objectType)
    {
        return objectType.IsAssignableFrom(typeof(IDictionary<string, string>));
    }
}

Then you should have the models as below in order to fetch the json into strongly typed objects. As u can see there is this attribute [JsonConverter(typeof(DataConverter))] which tells the converter how to serialize/deserialize the content.

[Serializable]
public class Table
{ 
    [JsonProperty("data")]
    [JsonConverter(typeof(DataConverter))]
    public Dictionary<string, string> Data { get; set; } 
}

[Serializable]
public class Content
{ 
    [JsonProperty("table")]
    public Table[] Tables { get; set; }
}

[Serializable]
public class MyObject
{
    [JsonProperty("content")]
    public Content Content { get; set; }
}

Here is a simple console app to test it: - be aware that i removed everything else under table for the sake of simplicity but you can add them in your app.

public static void Main()
{
    string content = @"{   
                        ""content"": {
                            ""table"": [
                                {
                                    ""data"": [
                                        ""154"",
                                        ""124254"",
                                        ""87575""             
                                    ]
                                }           
                              ]
                            }
                        }";

    var result = JsonConvert.DeserializeObject<MyObject>(content);
    foreach (var table in result.Content.Tables)
    { 
        Console.WriteLine(JsonConvert.SerializeObject(table));
    }
    Console.ReadLine();
}

Hope it helps :)

Answer 2

If this gives you some idea:

var json = "{'data': ['154','124254','87575']}";

dynamic obj = JsonConvert.DeserializeObject(json);

for (int i = 0; i < obj.data.Count; i++)
{
    dynamic val = new { id = i + 1, value = obj.data[i] };
    obj.data[i] = JsonConvert.SerializeObject(val);
}
var newJson = JsonConvert.SerializeObject(obj);