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 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/57987021/remove-replace-newline-character-from-json-in-net-using-jsonconvert

​

    public class ReplacingStringWritingConverter : JsonConverter

    {

        readonly string oldValue;

        readonly string newValue;

​

        public ReplacingStringWritingConverter(string oldValue, string newValue)

        {

            if (string.IsNullOrEmpty(oldValue))

                throw new ArgumentException("string.IsNullOrEmpty(oldValue)");

            if (newValue == null)

                throw new ArgumentNullException("newValue");

            this.oldValue = oldValue;

            this.newValue = newValue;

        }

​

        public override bool CanConvert(Type objectType)

        {

            return objectType == typeof(string);

        }

​

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

​

        public override bool CanRead { get { return false; } }

​

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

        {

            var s = ((string)value).Replace(oldValue, newValue);

            writer.WriteValue(s);

        }

    }

​

    class TestClass

    {

        public static void Test()

        {

            Test<JToken>();

        }   

        public static void Test<RootObject>()

        {

            var root = JsonConvert.DeserializeObject<RootObject>(GetJson());

            var settings = new JsonSerializerSettings { Converters = { new ReplacingStringWritingConverter("\n", "") } };

            var newJson = JsonConvert.SerializeObject(root, Formatting.None, settings);

            Console.WriteLine(newJson);

            // Assert the JSON string does not contain an escaped newline.

            Assert.IsTrue(!newJson.Contains("\\n"));

            var newJsonWithoutReplacing = JsonConvert.SerializeObject(root, Formatting.None);

​

            // Assert the default JSON serialization (i.e. without using the converter) does contain an escaped newline

            Assert.IsTrue(newJsonWithoutReplacing.Contains("\\n"));

        }   

        static string GetJson()

        {

            var json = @"{

        ""PolicyHolderInfo"": {

            ""ActionDate"": ""20190912"",

            ""EmployeeCode"": ""EPL2"",

            ""LocalEntityCode"": ""K"",

            ""PolicyHolderCode"": ""1YAAAAC"",

            ""Name1"": ""monoliability PDL\n"",

            ""Name2"": ""test\n"",

            ""Street1"": ""-"",

            ""Street2"": ""-"",

            ""City"": ""-"",

            ""PostCode"": ""-"",

            ""Subdivision"": ""01"",

            ""FMEPaymentFrequency1"": ""00"",       

            ""Reference"": ""C00-AAC""

        },

        ""PolicyHolderTrailerInfo"": {

            ""RecordCode"": ""Z"",

            ""CountryCode"": ""KSA"",

            ""SourceIndicator"": ""EPLC"",

            ""RecordSequence"": 0,

            ""LinkNumber"": 0,

            ""RecordType"": ""Z"",

            ""ReturnCode"": null,

            ""Reference"": ""1-AC""

        },

        ""SourceSystemDate"": ""2019-09-17T17:48:31.3543314+08:00""

    }

";

            return json;

        }

    }

​

​

    public class Program

    {

        public static void Main()

        {

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

            Console.WriteLine("Json.NET version: " + 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;

        }

    }

​