using System;

using System.Collections.Generic;

using System.IO;

using System.Data;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Serialization;

using System.Xml;

//https://stackoverflow.com/questions/46158581/serializing-a-datatable-with-byte-column-to-json-generate-base64-string-but-w

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Deseriialize DataTable to Json with byte[]");

        var dt = GetDataTable();

        //show table structure

        Console.WriteLine("The Original datatable structure");

        DumpTableStructure(dt);

        ITraceWriter traceWriter = new MemoryTraceWriter();

        var settings = new JsonSerializerSettings

                {

             TypeNameHandling =TypeNameHandling.Objects, 

                    TraceWriter = traceWriter,

                    Formatting = Newtonsoft.Json.Formatting.Indented,

                }; 

          settings.Converters.Add(new ByteConverter());

        var json = JsonConvert.SerializeObject(dt, settings);

          Console.WriteLine("-----json-------");

        Console.WriteLine(json);

        var dt2= JsonConvert.DeserializeObject<DataTable>(json, settings);

        Console.WriteLine("The generated datatable structure");

        DumpTableStructure(dt2);

    }

    public static DataTable GetDataTable()

        {

            DataTable dataTable = new DataTable("table");

            dataTable.Columns.Add("f1", typeof(byte[]));

            dataTable.Columns.Add("f2", typeof(string));

            dataTable.Columns.Add("id", typeof(int));

            dataTable.Columns.Add("mydatatable", typeof(DataTable));

            dataTable.Columns.Add("myEntity", typeof(Entity));

        DataRow newRow = dataTable.NewRow();        

            newRow["f1"] =  new byte[]{0xE6,0x10, 0x00,0x24,0x40 };

            newRow["f2"] = "hi all";

            newRow["id"] = 1;

            DataTable dataTable2 = new DataTable("table");

            dataTable2.Columns.Add("xyz", typeof(int));

             DataRow newRow2 = dataTable2.NewRow();                    

                    newRow2["xyz"]=99;

                    dataTable2.Rows.Add(newRow2);              

                newRow["mydatatable"] = dataTable2; 

        var entity = new Entity {id=1};

        newRow["myEntity"] = entity;

            dataTable.Rows.Add(newRow);

​

            newRow = dataTable.NewRow();

            newRow["f1"] = new byte[]{0xE6,0x1a, 0xf0,0x24,0x40 };

            newRow["f2"] = "hi world";

            newRow["id"] = 2;

            dataTable.Rows.Add(newRow);

            return dataTable;

        }

      public static  void DumpTableStructure(DataTable dt)

        {

            foreach (DataColumn column in dt.Columns)

            {

                Console.WriteLine("Name: {0} type: {1}", column.ColumnName, column.DataType);

            }

        }

}

​

class Entity

{

    public int id {get;set;}

}

​

//https://stackoverflow.com/questions/30369274/deserializing-base64-encoded-byte-arrays-return-different-results-in-2-json-net

    public class ByteConverter : JsonConverter

    {

        public override bool CanConvert(Type objectType)

        {

            return objectType == typeof(byte[]);

        }

​

        public override bool CanWrite { get { return false; } } // Use the default implementation for serialization, which is not broken.

​

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

        {

            var value = (string)JToken.Load(reader);

            if (value == null)

                return null;

            if (value.Length == 0)

                return new byte[0];

            return Convert.FromBase64String(value);

        }

​

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

        {

            throw new NotImplementedException();

        }

    }

​

​