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.

"Is it possible to use Newtonsoft.json.dll for this task?" Yes, of course. You can either directly process the Json data with the help of the JArray, JObject and other classes from Newtonsoft.Json. Or you can use Newtonsoft.Json to deserialize the original Json into objects of a class structure that matches the original Json layout, then process the data in your program based on those objects and construct another model/object tree based on (other) classes matching your desired new Json layout, and then finally serialize this back to json. — user2819245
– user2819245, Commented Mar 2, 2019 at 18:50
You could deserialize to a matching class structure and include a Type converter which will then output a converted structure for serialization. — Jimi
– Jimi, Commented Mar 2, 2019 at 20:24

Rey · Accepted Answer · 2019-03-03 12:06:37Z

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 :)

Mat · Accepted Answer · 2019-03-03 01:27:07Z

1

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);

edited Mar 3, 2019 at 1:27

Mat

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answered Mar 2, 2019 at 19:54

coffeebeans

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1 Comment

Mat Over a year ago

You should always try and give at least a little explanation to your answers so that people can understand how the code you provide solves the problem.

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