https://stackoverflow.com/questions/57987021/remove-replace-newline-character-from-json-in-net-using-jsonconvert

CSharp · Console

/Program.cs

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;
		}
	}