using System;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var jsonString = "{\"foo\": [{ \"abc\": \"bar\",\"xyua\": 7},{\"lkkj\": true},{\"babnd\": \"jhjkas\",\"ihdo\": 109,\"daers\": true}],\"ewq\": 7,\"inh\": null,\"bhj\": true,\"test\": null,\"booltest\": false}";

        var jsonObj = JObject.Parse(jsonString);

        var resultJsonObj = JsonExtensions.ReplacePath(jsonObj, "$.foo[0].abc", "*********");

        resultJsonObj = JsonExtensions.ReplacePath(resultJsonObj, "$.foo[2].babnd", true);      

        resultJsonObj = JsonExtensions.ReplacePath(resultJsonObj, "$.ewq", 8008);

        var outputResult = resultJsonObj.ToString(Formatting.None);

        Console.WriteLine(outputResult);

    }

}

​

    static class JsonExtensions

    {

        public static JObject ReplacePath<T>(this JToken root, string path, T newValue)

        {

            if (root == null || path == null)

            {

                throw new ArgumentNullException();

            }

​

            foreach (var value in root.SelectTokens(path).ToList())

            {

                if (value == root)

                {

                    root = JToken.FromObject(newValue);

                }

                else

                {

                    value.Replace(JToken.FromObject(newValue));

                }

            }

​

            return (JObject)root;

        }

​

        public static string ReplacePath<T>(string jsonString, string path, T newValue)

        {

            return JToken.Parse(jsonString).ReplacePath(path, newValue).ToString();

        }

    }