using System;

using AutoMapper;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var config = new MapperConfiguration(cfg =>

        {

            cfg.CreateMap<VehicleEntity, VehicleDto>()

                //.ForMember(dest => dest.NumberPlaces, opt => opt.MapFrom(src => src.NumberPlacesStr));

                .ForMember(dest => dest.NumberPlaces, opt => opt.MapFrom<VehicleNumberPlacesResolver>());

        });

        IMapper mapper = config.CreateMapper();

        VehicleEntity src = new VehicleEntity

        {

            Id = 1,

            NumberPlacesStr = "A2345"

        };

        VehicleDto dest = mapper.Map<VehicleDto>(src);

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

    }

}

​

public class VehicleEntity 

{

    public int Id { get; set; }

    public string AddressNumber { get; set; }

    public string VehicleNumber { get; set; }

    public string Brand { get; set; }

    public string NumberPlacesStr { get; set; }

}

​

public class VehicleDto 

{

    public int Id { get; set; }

    public string AddressNumber { get; set; }

    public string VehicleNumber { get; set; }

    public string Brand { get; set; }

    public int NumberPlaces { get; set; }

}

​

public class VehicleNumberPlacesResolver : IValueResolver<VehicleEntity, VehicleDto, int>

{

    public int Resolve(VehicleEntity source, VehicleDto destination, int member, ResolutionContext context)

    {

        try

        {

            return Int32.Parse(source.NumberPlacesStr);

        }

        catch

        {

            return default;

        }

    }

}