using System;

using System.Linq;

using System.Collections.Generic;

using System.Collections;

using Newtonsoft.Json;

using Newtonsoft.Json.Serialization;

​

public class Program

{

    public static void Main()

    {

        var input = "{\"logtype_Description\":\"whatever\"}";

        var deserializeSettings = new JsonSerializerSettings{ContractResolver = new DefaultContractResolver{NamingStrategy = new SnakeCaseNamingStrategy()}};

        var deserialized = JsonConvert.DeserializeObject<MyModel>(input, deserializeSettings);

        deserialized.LogtypeDescription = "new content";

        var serializeSettings = new JsonSerializerSettings{ContractResolver = new DefaultContractResolver{NamingStrategy = new CamelCaseNamingStrategy()}};

        var serialized = JsonConvert.SerializeObject(deserialized);

        Console.Write(serialized);

    }

}

​

public class MyModel

{

    public string LogtypeDescription

    {

        get;

        set;

    }

}