using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

using System.Collections.ObjectModel;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

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

​

//https://stackoverflow.com/questions/63674113/how-to-replace-json-from-another-json-in-c-sharp-using-newtonsoft

​

    class TestClass

    {

        public static void Test()

        {

            var req1 = @"{

    ""payload"": {

        ""firstName"": ""John"",

        ""lastName"": ""Doe"",

        ""code"": ""test1"",

        ""arrayProp1"": [1, 2, 3],

        ""arrayProp2"": [{

                ""prop1"": ""value1"",

                ""prop2"": ""value2""

            },

            {

                ""prop1"": ""2_value1"",

                ""prop2"": ""2_value2""

            }

        ]

    }

}";

            var req2 = @"{

    ""payload"": {

        ""code"": ""newCode"",

        ""arrayProp1"": [3,4],

        ""arrayProp2"": [{

                ""prop1"": ""newValue1"",

                ""prop2"": ""newValue2""

            }

        ]

    }

}";

            var requiredJsonString = @"{

    ""payload"": {

        ""firstName"": ""John"",

        ""lastName"": ""Doe"",

        ""code"": ""newCode"",

        ""arrayProp1"": [3, 4],

        ""arrayProp2"": [{

            ""prop1"": ""newValue1"",

            ""prop2"": ""newValue2""

        }]

    }

}";

            var json1 = JObject.Parse(req1);

            var json2 = JObject.Parse(req2);

            json1.Merge(json2, new JsonMergeSettings 

                        { 

                            MergeArrayHandling = MergeArrayHandling.Replace 

                        });

            Console.WriteLine(json1);

            Assert.IsTrue(JToken.DeepEquals(json1, JToken.Parse(requiredJsonString)));

        }   

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1})", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , GetNetCoreVersion());

            Console.WriteLine("{0} version: {1}", typeof(JsonSerializer).Assembly.GetName().Name,  typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

        public static string GetNetCoreVersion()

        {

            //https://techblog.dorogin.com/how-to-detect-net-core-version-in-runtime-ecd65ad695be

            //

            var assembly = typeof(System.Runtime.GCSettings).GetTypeInfo().Assembly;

            var assemblyPath = assembly.CodeBase.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);

            int netCoreAppIndex = Array.IndexOf(assemblyPath, "Microsoft.NETCore.App");

            if (netCoreAppIndex > 0 && netCoreAppIndex < assemblyPath.Length - 2)

                return assemblyPath[netCoreAppIndex + 1];

            return null;

        }

    }

​