JSON parsing using c# and LitJson

Question

I have a JSON data (file attached). How can I parse it using C# using LitJSON? I am having trouble in deserialising it. Any help would be appreciated.

{
"vr-sessions" : {
"-KvDNAFD_BxlKEJ958eX" : {
  "interview" : "Android",
  "questions" : {
    "-KvG7BuWu4eI52pq-6uH" : {
      "playaudio" : "audio1",
      "question" : "Why cannot you run standard Java bytecode on Android?"
    },
    "-KvG9rxQv5DWJa1EMnhi" : {
      "playaudio" : "audio2",
      "question" : "Where will you declare your activity so the system can access it?"
    }
  }
},
"-KvDNOE8YhVdgovxrzrN" : {
  "interview" : "DevOps",
  "questions" : {
    "-KvMPd0v9BXnjYZxFm5Q" : {
      "playaudio" : "audio3",
      "question" : "Explain what is DevOps?"
    },
    "-KvMPi24OKeQTp8aJI0x" : {
      "playaudio" : "audio4",
      "question" : "What are the core operations of DevOps with application development and with infrastructure?"
    },
    "-KvMPqYxJunKp2ByLZKO" : {
      "playaudio" : "audio5",
      "question" : "Explain how “Infrastructure of code” is processed or executed in AWS?"
    }
  }
},

@shaw it looks like he is only copying the first two objects of the json string. — vipersassassin
– vipersassassin, Commented Oct 15, 2017 at 15:26
Have you tried parsing it with LitJson? What happened? Please provide a minimal reproducible example showing how far you've got, and what happened. — Jon Skeet
– Jon Skeet, Commented Oct 15, 2017 at 15:49
@vipersassassin You are right. There are many objects like that. Could not copy all here. Sorry for not closing the JSON with brackets at the end. — Manish Kumar
– Manish Kumar, Commented Oct 16, 2017 at 8:43
@ManishKumar post a proper sample, code and an explanation of the problem. Don't force people to guess what the question is. "What's wrong" isn't a question. Also provide a link to LitJson. Google returns links to an abandoned Github project. Why don't you use an up-to-date deserializer like Json.NET? — Panagiotis Kanavos
– Panagiotis Kanavos, Commented Oct 16, 2017 at 10:51

Daniel Manta · Accepted Answer · 2017-10-16 11:24:16Z

2

After adding a couple of missing braces and removing last comma, your json seems to be valid. However there's no way to declare a class or member starting with dash in C#. Not sure how LitJson would be able to map json values to a C# class if names don't match, unless you replace dashes before parsing the string with LitJson.

Workaround

In your Solution Explorer right click References and do Add Reference, then from Assemblies->Framework select System.Web.Extensions.

string jsonString = File.ReadAllText("json.txt");
dynamic json = new JavaScriptSerializer().Deserialize<dynamic>(jsonString);

Navigate to the value you're looking for

string interview = json["vr-sessions"]["-KvDNAFD_BxlKEJ958eX"]["interview"];

Variable interview gets value "Android" which is the same as doing this:

var sessions = json["vr-sessions"];
string interview = sessions["-KvDNAFD_BxlKEJ958eX"]["interview"];

If you don't know session names

Iterate to get question and playaudio values.

foreach (var session in json["vr-sessions"].Values)
{
    foreach (var question in session["questions"].Values)
    {
        Console.WriteLine(question["question"]);
        Console.WriteLine(question["playaudio"]);
    }
}

Access to an element by position: let's say you want to iterate 0..N

var sessions = new List<dynamic>(json["vr-sessions"].Values);
Console.WriteLine(sessions[0]["interview"]);

This prints "Android" as the value of interview for session at position 0 is "Android".

edited Oct 16, 2017 at 11:24

answered Oct 15, 2017 at 16:31

Daniel Manta

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2 Comments

Manish Kumar Over a year ago

Thanks for the code. But I don't know "-KvDNAFD_BxlKEJ958eX" in advance. And there are many keys like that, around 100. How can I access "playaudio" or "question" in this scenario?

Daniel Manta Over a year ago

If you don't know session's name the only way to go is using a dynamic object like the above. I have updated my answer to show you how to iterate and get those values, ignoring session names.

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