Question

I’m trying to deserialize JSON in this format:

{
   "data": [
      {
         "installed": 1,
         "user_likes": 1,
         "user_education_history": 1,
         "friends_education_history": 1,
         "bookmarked": 1
      }
   ]
}

to a simple string array like this:

{
    "installed",
    "user_likes",
    "user_education_history",
    "friends_education_history",
    "bookmarked"
}

using JSON.NET 4.0

I’ve gotten it to work using the `CustomCreationConverter’

public class ListConverter : CustomCreationConverter<List<string>>
{
public override List<string> Create(Type objectType)
{
    return new List<string>();
}

public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
    var lst = new List<string>();

    //don't care about the inital 'data' element
    reader.Read();

    while (reader.Read())
    {
        if (reader.TokenType == JsonToken.PropertyName)
        {
            lst.Add(reader.Value.ToString());
        }
    }
    return lst;
}
}

but this really seems like overkill, especially if I want to create one for many different json responses.

I’ve tried using JObject but it doesn’t seem like I’m doing it right:

List<string> lst = new List<string>();
JObject j = JObject.Parse(json_string);
foreach (JProperty p in j.SelectToken("data").Children().Children())
{
    lst.Add(p.Name);
}

Is there a better way to do this?

Answer 1

There are many ways you can do that, and what you have is fine. A few other alternatives are shown below:

• Get the first element of the array, instead of all the children

• Use SelectToken to go to the first array element with a single call

      string json = @"{
        ""data"": [
          {
            ""installed"": 1,
            ""user_likes"": 1,
            ""user_education_history"": 1,
            ""friends_education_history"": 1,
            ""bookmarked"": 1
          }
        ]
      }";
  
      JObject j = JObject.Parse(json);
  
      // Directly traversing the graph
      var lst = j["data"][0].Select(jp => ((JProperty)jp).Name).ToList();
      Console.WriteLine(string.Join("--", lst));
  
      // Using SelectToken
      lst = j.SelectToken("data[0]").Children<JProperty>().Select(p => p.Name).ToList();
      Console.WriteLine(string.Join("--", lst));