Add property to each object in JSON C#

January 24, 2022

I have a JSON body which looks like this(an array of objects):

[
    {
        "registered": "2016-02-03T07:55:29",
        "color": "red",
    },
    {
        "registered": "2016-02-03T17:04:03",
        "color": "blue",
    }
]

This body is contained in a variable(requestBody) I create based on a HTTP Request, it’s called req:

string requestBody = await new StreamReader(req.Body).ReadToEndAsync();

What I want to do is add a unique identifier to each one of the objects in my JSON array. How could I go about achieving this?

Currently I am deserializing the JSON, adding some string(x) to it and then serializing it again:

dynamic d = JsonConvert.DeserializeObject(requestBody);
d.uniqueId = "x";
string newBody = JsonConvert.SerializeObject(d);

I was to add a uniqueId to each one of the objects in my JSON array of objects. How could I achieve this?

>Solution :

You can use JArray from LINQ to JSON API to parse, iterate children of JObject type and modify them:

var json = ...; // your json string
var jArray = JArray.Parse(json);
foreach (var jObject in jArray.Children<JObject>())
{
    jObject.Add("id", new JValue("x"));
}
var modified = JsonConvert.SerializeObject(jArray);