using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

using System.Collections.ObjectModel;

using System.Reflection;

using System.Runtime.Serialization;

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;

​

// https://stackoverflow.com/questions/42290485/json-net-get-nested-jtoken-value

​

    public class Solr_User

    {

        public int id { get; set; }

        public string first_name { get; set; }

        public string _version_ { get; set; }

    }

​

    class TestClass

    {

        static string GetJson()

        {

            var json = @"{

      ""responseHeader"":{

        ""status"":0,

        ""QTime"":0,

        ""params"":{

          ""q"":""*:*"",

          ""indent"":""on"",

          ""wt"":""json""}},

      ""response"":{""numFound"":4,""start"":0,""docs"":[

          {

            ""id"":3,

            ""first_name"":""Bob"",

            ""_version_"":""1558902640594649088""},

          {

            ""id"":4,

            ""first_name"":""Sam"",

            ""_version_"":""1558902640613523456""},

          {

            ""id"":2,

            ""first_name"":""Fred"",

            ""_version_"":""1558902640613523457""},

          {

            ""id"":1,

            ""first_name"":""Max"",

            ""_version_"":""1558902640613523458""}]

      }}";

            return json;

        }

        internal static void Test()

        {

            var text = GetJson();

            Console.WriteLine("Testing full JSON: ");

            TestOneLine(text);

            TestTwoLinesLine(text);

            // Remove the docs token

            var test = JToken.Parse(text);

            test.SelectToken("response.docs").Parent.Remove();

            Console.WriteLine("Testing JSON with \"response.docs\": removed: ");

            TestOneLine(test.ToString());

            // Remove the response  token

            test.SelectToken("response").Parent.Remove();

            TestOneLine(test.ToString());

            // Adding an invalid response

            test["response"] = "an invalid response";

            TestOneLine(test.ToString());

​

            Console.Write("Verifying that the index operator throws an exception for an index of the wrong type: ");    

            Assert.Throws(Is.InstanceOf(typeof(Exception)), () => Console.WriteLine(test["response"]["docs"]));

            Console.Write(" ... passed.");  

        }

        static void TestTwoLinesLine(string text)

        {

            var jObj = JObject.Parse( text );

            //var su = jObj.SelectToken("response.docs")?.ToObject<Solr_User []>(); // In c# 6 or later

            var token = jObj.SelectToken("response.docs");

            var su = token == null ? null : token.ToObject<Solr_User []>();

            Console.WriteLine(JsonConvert.SerializeObject(su, Formatting.Indented));

        }

        static void TestOneLine(string text)

        {

            var jObj = JObject.Parse( text );

            //var su = jObj.SelectToken("response.docs")?.ToObject<Solr_User []>(); // In c# 6 or later

            var su = (jObj.SelectToken("response.docs") ?? JValue.CreateNull()).ToObject<Solr_User []>();

            Console.WriteLine(JsonConvert.SerializeObject(su, Formatting.Indented));

        }

    }

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Json.NET version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine("");

            TestClass.Test();

        }

    }