using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

using System.Data;

using System.Globalization;

using System.Reflection;

​

using System.Drawing;

​

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/67940579/c-sharp-json-custom-serialization-of-class-including-attributes-of-members-prope

​

    [System.AttributeUsage(System.AttributeTargets.Property | System.AttributeTargets.Field, AllowMultiple = false, Inherited = true)]

    public class CustomTypeAttribute : System.Attribute

    {

        public CustomTypeAttribute(string type) => this.Type = type;

        public string Type { get; set; }

    }

​

    public class ObjectAsAllPropsConverter<TBase> : JsonConverter

    {

        const string AllPropsName = "AllProps";

        const string KeyName = "Key";

        const string ValueName = "Value";

        const string TypeName = "Type";

        const string DefaultType = "0";

        static IContractResolver DefaultResolver { get; } = JsonSerializer.CreateDefault().ContractResolver;

        readonly IContractResolver resolver;

        public ObjectAsAllPropsConverter() : this(DefaultResolver) { }

        public ObjectAsAllPropsConverter(IContractResolver resolver) => this.resolver = resolver ?? throw new ArgumentNullException(nameof(resolver));

        public override bool CanConvert(Type objectType)

        {

            if (objectType.IsPrimitive || objectType == typeof(string) || !typeof(TBase).IsAssignableFrom(objectType))

                return false;

            return resolver.ResolveContract(objectType) is JsonObjectContract;

        }

​

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

        {

            var contract = (JsonObjectContract)serializer.ContractResolver.ResolveContract(value.GetType());

            writer.WriteStartObject();

            writer.WritePropertyName(AllPropsName);

            writer.WriteStartArray();

            foreach (var property in contract.Properties.Where(p => ShouldSerialize(p, value)))

            {

                var propertyValue = property.ValueProvider.GetValue(value);

                if (propertyValue == null && (serializer.NullValueHandling == NullValueHandling.Ignore || property.NullValueHandling == NullValueHandling.Ignore))

                    continue;

                writer.WriteStartObject();

                writer.WritePropertyName(KeyName);

                writer.WriteValue(property.PropertyName);

                writer.WritePropertyName(ValueName);

                if (propertyValue == null)

                    writer.WriteNull();

                else if (property.Converter != null && property.Converter.CanWrite)

                    property.Converter.WriteJson(writer, propertyValue, serializer);

                else

                    serializer.Serialize(writer, propertyValue);

                writer.WritePropertyName(TypeName);

                var type = property.AttributeProvider.GetAttributes(typeof(CustomTypeAttribute), true).Cast<CustomTypeAttribute>().SingleOrDefault()?.Type ?? DefaultType;

                writer.WriteValue(type);

                writer.WriteEndObject();

            }

            writer.WriteEndArray();

            writer.WriteEndObject();

        }

​

        protected virtual bool ShouldSerialize(JsonProperty property, object value) =>

            property.Readable && !property.Ignored && (property.ShouldSerialize == null || property.ShouldSerialize(value));

​

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) => throw new NotImplementedException();

    }

​

    public partial class MyClass

    {

        [JsonProperty("prop1")]

        public string Prop1 { get; set; }

        [JsonProperty("prop2")]

        [CustomType("somevalue")]

        public string Prop2 { get; set; }

        //

        //

        [JsonProperty("propn")]

        [CustomType("anothervalue")]

        public string PropN { get; set; }

    }

​

    public partial class MyClass

    {

        [CustomType("Color")]

        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]

        [JsonConverter(typeof(TestColorConverter))]

        public Color? Color { get; set; }

        [CustomType("ListOfStrings")]

        public List<string> List { get; } = new ();

        public bool ShouldSerializeList() => List?.Count > 0;

    }

​

    class TestClass

    {

        public static void Test()

        {

            var myClass = new MyClass

            {

                Prop1 = "value of prop1",

                Prop2 = "value of prop2",

                PropN = "value of propn",

            };

​

            var settings = new JsonSerializerSettings

            {

                Converters = { new ObjectAsAllPropsConverter<object>() },

            };

            var json = JsonConvert.SerializeObject(myClass, Formatting.Indented, settings);

            Console.WriteLine(json);

            var token = JObject.FromObject(myClass, JsonSerializer.CreateDefault(settings));

            Assert.IsTrue(JToken.DeepEquals(JToken.Parse(GetRequiredJson()), token));

            // Verify that the JsonConverter applied to a property is invoked.

            myClass.Color = Color.AliceBlue;

            myClass.List.Add("Hello");

​

            var json2 = JsonConvert.SerializeObject(myClass, Formatting.Indented, settings);

            Console.WriteLine(json2);

            Assert.IsTrue(json2.Contains(myClass.Color.Value.ToHtml()));

        }   

        static string GetRequiredJson() => @"    {

    ""AllProps"": [

        {

            ""Key"": ""prop1"",

            ""Value"": ""value of prop1"",

            ""Type"": ""0""

        },

        {

            ""Key"": ""prop2"",

            ""Value"": ""value of prop2"",

            ""Type"": ""somevalue""

        },

        {

            ""Key"": ""propn"",

            ""Value"": ""value of propn"",

            ""Type"": ""anothervalue""

        }

    ]

}";

    }

​

    public static class ColorExtensions

    {

        public static string ToHtml(this Color c)

        {

            return string.Format("rgba({0},{1},{2},{3})", c.R, c.G, c.B, c.A / 255f);

        }

    }

​

    public class TestColorConverter : JsonConverter

    {

        public override bool CanConvert(Type objectType) => objectType == typeof(Color) || objectType == typeof(Color?);

​

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) => throw new NotImplementedException();

​

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

        {

            if (value == null)

                writer.WriteNull();

            else

            {

                var c = (Color)value;

                writer.WriteValue(c.ToHtml());

            }

        }

    }

​

    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.Location.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;

        }

    }

​