using System;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    public class NamesModel{

        public string firstname {get; set;}

        public string gender {get;set;}

    }

    public static void Main()

    {

        var json = @"{

            'names': [

                {

                    'firstname': 'Sven', 'gender': 'male'

                },

                {

                    'firstname': 'Roger','gender': 'male'

                },

                {

                    'firstname': 'Siv','gender': 'female'

                }

            ]

        }";

        var names = JsonConvert.DeserializeObject<Dictionary<string, List<NamesModel>>>(json);

        foreach(KeyValuePair<string, List<NamesModel>> entry in names)

        {

            foreach(var value in entry.Value){

                Console.WriteLine(value.firstname);

                Console.WriteLine(value.gender);

            }

        }

    }

}