Extract first element from JSON

Question

How can I take just the first element from a Json?

//take result back
    void HandleIncomingMessage(object sender, PEventArgs e)
    {
        RetMessage += e.Result;
        //here can not deserialize correct
        var deserialized_message = JsonConvert.DeserializeObject<Message>(RetMessage);
    }

Here I am doing the deserialize but because it`s taking the entire object can not parse it correct.

I need just JSON.[0]

Edit: Raw Json :

 [{"unique_id":55,"action_name":"INSERT","start_date":"2018-06-11T16:00:00","end_date":"2018-06-11T17:00:00"},"1sddsd","my_channel"]

This question would be greatly improved if you posted the raw JSON string and not an image of the debug pane. — John Wu, Jun 11 '18 at 09:40
Possible duplicate of [How to parse huge JSON file as stream in Json.NET?](https://stackoverflow.com/questions/43747477/how-to-parse-huge-json-file-as-stream-in-json-net) — ProgrammingLlama, Jun 11 '18 at 09:51
I know the duplicate isn't identical to your problem, but it shows how you can read JSON gradually rather than all at once. — ProgrammingLlama, Jun 11 '18 at 09:51
Since your json is unstructured, you need to use dynamic parsing, parse it into a `JArray`, then grab the first element and deserialize that to your `Message` type. — Lasse V. Karlsen, Jun 11 '18 at 09:53

John Wu · Accepted Answer · 2018-06-11T10:11:41.577

9

Deserialize to List<dynamic>, then read the properties of its first element.

//using Newtonsoft.Json;
var input = @"[{""unique_id"":55,""action_name"":""INSERT"",""start_date"":""2018-06-11T16:00:00"",""end_date"":""2018-06-11T17:00:00""},""1sddsd"",""my_channel""]";
var output = JsonConvert.DeserializeObject<List<dynamic>>(input);
Console.WriteLine(output[0].unique_id);

Output:

55

DotNetFiddle

edited Jun 11 '18 at 10:11

answered Jun 11 '18 at 10:06

John Wu

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You are right, this helps me to deserialize it. Thanks! – Alexandra Damaschin Jun 11 '18 at 10:44

score 1 · Answer 2 · answered Jun 11 '18 at 09:55

1

How about getting json string and using JSON.net

//first create object from json
JObject jObject = JObject.Parse(jsonString);
//read unique value        
string jUniqueId = jObject["unique_id"];
//or
string firstObject = jObject[0];

answered Jun 11 '18 at 09:55

aditya

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1
8

2

You mean `JArray.Parse`. – Lasse V. Karlsen Jun 11 '18 at 09:57
No, IT IS `JObject.Parse` of `Newtonsoft.Json.Linq` – Weihui Guo Sep 22 '19 at 00:04

Mohan Srinivas · Answer 3 · 2018-06-11T10:04:41.567

-3

the solution is for static,

JObject obj= JObject.Parse(here pass the JSON);
  string id=  JSON[0]["unique_id"],
  string name=  JSON[0]["action_name"],
  string sdate=  JSON[0]["start_date"],
  string edate=  JSON[0]["end_date"]

dynamic means pass i instead of 0.

edited Jun 11 '18 at 10:04

answered Jun 11 '18 at 09:50

Mohan Srinivas

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Reason for downvote: What is `JSON`? Where does `JSON` come from? – ProgrammingLlama Jun 11 '18 at 09:59
You now have the same issue as aditya. – ProgrammingLlama Jun 11 '18 at 10:43

Extract first element from JSON

3 Answers3