using System;

using Newtonsoft.Json;

​

namespace Sandbox

{

    public class KeyValue

    {

        public string Key { get; set; }

        public string Value { get; set; }       

    }

    public class Program

    {

        public static void Main()

        {

            var json = "{\"Key\": 'test', \"Value\": 210001.0}";

            var kvdbl = JsonConvert.DeserializeObject<KeyValue>(json, new JsonSerializerSettings { FloatParseHandling = FloatParseHandling.Double });

            Console.WriteLine("With Double: " + kvdbl.Value);

            var kvdcml = JsonConvert.DeserializeObject<KeyValue>(json, new JsonSerializerSettings { FloatParseHandling = FloatParseHandling.Decimal });

            Console.WriteLine("With Decimal: " + kvdcml.Value);

        }

    }

}