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.Diagnostics;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

// https://stackoverflow.com/questions/46371420/jsonconverter-and-entitydata/

​

    namespace StrictConverters

    {

        class IntConverter : JsonConverter

        {

            public override bool CanConvert(Type objectType)

            {

                return objectType == typeof(int) || objectType == typeof(int?);

            }

​

            public override object ReadJson(JsonReader reader, Type objectType,

                object existingValue, JsonSerializer serializer)

            {

                switch (reader.TokenType)

                {

                    case JsonToken.Null:

                        return null;

​

                    case JsonToken.Integer:

                        // Input was already an integer.  Return it

                        return (int)JToken.Load(reader);

​

                    case JsonToken.String:

                        {

                            int num;

                            if (Int32.TryParse(reader.Value.ToString(), NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out num))

                                return num;

                            else

                                return 0;

                        }

​

                    default:

                        throw new JsonSerializationException(string.Format("Unexpected token {0} at path {1}", reader.TokenType, reader.Path));

                }

            }

​

            public override void WriteJson(JsonWriter writer, object value,

                JsonSerializer serializer)

            {

                // Int32 implements the IConvertible interface which has a ToString() overload

                // that takes an IFormatProvider specification.  Pass the invariant format to guarantee

                // identical serialization in all cultures.

                var convertible = (IConvertible)value;

                serializer.Serialize(writer, convertible.ToString(NumberFormatInfo.InvariantInfo));

            }

        }

    }

​

    namespace TolerantConverters

    {

        class IntConverter : JsonConverter

        {

            public override bool CanConvert(Type objectType)

            {

                return objectType == typeof(int) || objectType == typeof(int?);

            }

​

            public override object ReadJson(JsonReader reader, Type objectType,

                object existingValue, JsonSerializer serializer)

            {

                switch (reader.TokenType)

                {

                    case JsonToken.Null:

                        return null;

​

                    case JsonToken.Integer:

                        // Input was already an integer.  Return it

                        return (int)JToken.Load(reader);

​

                    case JsonToken.String:

                        {

                            int num;

                            if (Int32.TryParse(reader.Value.ToString(), NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out num))

                                return num;

                            else

                                return 0;

                        }

​

                    default:

                        Debug.WriteLine(string.Format("Unexpected token {0} at path {1}", reader.TokenType, reader.Path));

                        reader.Skip();

                        return 0;

                }

            }

​

            public override void WriteJson(JsonWriter writer, object value,

                JsonSerializer serializer)

            {

                // Int32 implements the IConvertible interface which has a ToString() overload

                // that takes an IFormatProvider specification.  Pass the invariant format to guarantee

                // identical serialization in all cultures.

                var convertible = (IConvertible)value;

                serializer.Serialize(writer, convertible.ToString(NumberFormatInfo.InvariantInfo));

            }

        }

    }

​

    class Company

    {

        public int? Id { get; set; }

​

        public string CompanyName { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var companyName = "name";

​

            foreach (var converter in new JsonConverter[] { new TolerantConverters.IntConverter(), new StrictConverters.IntConverter() })

            {

                Console.WriteLine(string.Format("\nTesting {0}", converter));

​

                foreach (var json in GetJson(companyName))

                {

                    Test(json, converter, companyName);

                }

            }

​

            Console.WriteLine("Done");

        }

​

        static void Test(string json, JsonConverter converter, string companyName)

        {

            Console.WriteLine("\nInput JSON: ");

            Console.WriteLine(json);

​

            try

            {

                var company = JsonConvert.DeserializeObject<Company>(json, new[] { converter });

                var json2 = JsonConvert.SerializeObject(company, Formatting.Indented, new[] { converter });

​

                Console.WriteLine("Re-serialized JSON: ");

                Console.WriteLine(json2);

                Assert.IsTrue(company.CompanyName == companyName);

            }

            catch (AssertionFailedException ex)

            {

                Console.WriteLine(ex);

                throw;

            }

            catch (Exception ex)

            {

                Console.WriteLine(ex.Message);

            }

        }

​

        static IEnumerable<string> GetJson(string companyName)

        {

            var jsons = new List<string>();

​

            var company = JToken.FromObject(new Company { Id = 101, CompanyName = companyName });

            jsons.Add(company.ToString(Formatting.None));

​

            company["Id"] = "101";

            jsons.Add(company.ToString(Formatting.None));

​

            company["Id"] = null;

            jsons.Add(company.ToString(Formatting.None));

​

            company["Id"] = "bad 101";

            jsons.Add(company.ToString(Formatting.None));

​

            company["Id"] = DateTime.Today.ToUniversalTime();

            jsons.Add(company.ToString(Formatting.None));

​

            company["Id"] = company;

            jsons.Add(company.ToString(Formatting.None));

​

            company["Id"] = new JArray(new[] { company, company });

            jsons.Add(company.ToString(Formatting.None));

​

            return jsons;

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: " + Environment.Version);

            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 class AssertionFailedException : System.Exception

    {

        public AssertionFailedException() : base() { }

​

        public AssertionFailedException(string s) : base(s) { }

    }

​

    public static class Assert

    {

        public static void IsTrue(bool value)

        {

            IsTrue(value, "failed");

        }

​

        public static void IsTrue(bool value, string message)

        {

            if (value == false)

                throw new AssertionFailedException(message ?? "failed");

        }

    }

​