using System;

using System.Collections.Generic;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        var item1 = new DatamapItem();

        item1.datamapKey = new DatamapKey();

        item1.datamapKey.DatamapKeyFields.Add("module", 1);

        item1.datamapKey.DatamapKeyFields.Add("id", 1391);

        item1.DatamapItemFields.Add("paramName", "VE8321C");

        item1.DatamapItemFields.Add("min", "0");

        item1.DatamapItemFields.Add("max", "40");

        var item2 = new DatamapItem();

        item2.datamapKey = new DatamapKey();

        item2.datamapKey1 = new DatamapKey1();

        item2.DatamapItemFields.Add("paramName", "VE8321C");

        item2.DatamapItemFields.Add("min", "0");

        item2.DatamapItemFields.Add("max", "40");

​

        var item3 = new DatamapItem();

        item3.datamapKey = new DatamapKey();

        item3.datamapKey.DatamapKeyFields.Add("module", 1);

        item3.datamapKey.DatamapKeyFields.Add("id", 1391);

        item3.datamapKey1 = new DatamapKey1();

        item3.datamapKey1.DatamapKey1Fields.Add("module", 1);

        item3.datamapKey1.DatamapKey1Fields.Add("id", 1391);

        item3.DatamapItemFields.Add("paramName", "VE8321C");

        item3.DatamapItemFields.Add("min", "0");

        item3.DatamapItemFields.Add("max", "40");

        var root = new RootObject

        {

            datamapItems = new List<DatamapItem> { item1, item2, item3 }

        };

​

        var json = JsonHelper.SerializeToMinimalJson(root);

​

        Console.WriteLine(json);

    }

}

​

public class DatamapKey

{

    [JsonExtensionData]

    public Dictionary<string, JToken> DatamapKeyFields = new Dictionary<string, JToken>();

}

public class DatamapKey1

{

    [JsonExtensionData]

    public Dictionary<string, JToken> DatamapKey1Fields = new Dictionary<string, JToken>();

}

public class DatamapItem

{

    [JsonExtensionData]

    public Dictionary<string, JToken> DatamapItemFields { get; set; }

    public DatamapKey datamapKey { get; set; }

    public DatamapKey1 datamapKey1 { get; set; }

    public DatamapItem()

    {

        DatamapItemFields = new Dictionary<string, JToken>();

    }

}

public class RootObject

{

    public List<DatamapItem> datamapItems { get; set; }

}

​

​

public static class JsonHelper

{

    public static string SerializeToMinimalJson(object obj)

    {

        return JToken.FromObject(obj).RemoveEmptyChildren().ToString();

    }

​

    public static JToken RemoveEmptyChildren(this JToken token)

    {

        if (token.Type == JTokenType.Object)

        {

            JObject copy = new JObject();

            foreach (JProperty prop in token.Children<JProperty>())

            {

                JToken child = prop.Value;

                if (child.HasValues)

                {

                    child = child.RemoveEmptyChildren();

                }

                if (!child.IsNullOrEmpty())

                {

                    copy.Add(prop.Name, child);

                }

            }

            return copy;

        }

        else if (token.Type == JTokenType.Array)

        {

            JArray copy = new JArray();

            foreach (JToken item in token.Children())

            {

                JToken child = item;

                if (child.HasValues)

                {

                    child = child.RemoveEmptyChildren();

                }

                if (!child.IsNullOrEmpty())

                {

                    copy.Add(child);

                }

            }

            return copy;

        }

        return token;

    }

​

    public static bool IsNullOrEmpty(this JToken token)

    {

        return token == null ||

               (token.Type == JTokenType.Array && !token.HasValues) ||

               (token.Type == JTokenType.Object && !token.HasValues) ||

               (token.Type == JTokenType.String && token.ToString() == String.Empty) ||

               (token.Type == JTokenType.Null);

    }

​

}