using System;

using System.Linq;

using System.Collections.Generic;

using Newtonsoft.Json;

using Google.Protobuf.Collections;

using AutoMapper;

​

public class Program

{

    public class Wrapper1{

        public List<View1> List{get;set;} 

    }

    public class Wrapper2{

        public MapField<string, View2> Fields{get;set;} 

    }

    public class View1{

        public string Name{get;set;}

        public string LastName{get;set;}

        public string NationalCode{get;set;}

    }

    public class View2{

        public string Name{get;set;}

        public string LastName{get;set;}

        public string NationalCode{get;set;}

    }

    public static void Main()

    {

        var list = new List<View1>()

        {

            new View1 {

                Name = "a1",

                LastName ="b1",

                NationalCode = "1"

            },

            new View1 {

                Name = "a2",

                LastName ="b2",

                NationalCode = "2"

            }

        };

        var config = new MapperConfiguration(cfg => {

            cfg.CreateMap<View1, View2>();          

            cfg.CreateMap<Wrapper1, Wrapper2>()

                .ForMember(x=> x.Fields, x=> x.MapFrom(y=> y.List.ToDictionary(z=> z.NationalCode, w=> w)));

        });

        var mapper = config.CreateMapper();

        var wrapper1 = new Wrapper1{ List= list};

        var wrapper2 = mapper.Map<Wrapper2>(wrapper1);

        Console.WriteLine(JsonConvert.SerializeObject(wrapper2));

    }

}

​