using System;

using AutoMapper;

​

public class Item

{

    public MovieMetadata MovieMetadata { get; set; }

​

    public BookMetadata BookMetadata { get; set; }

}

​

public class MovieMetadata

{

    public string Title { get; set; }

}

​

public class BookMetadata

{

    public string Title { get; set; }

}

​

public class ItemDetail

{

    public string Title { get; set; }

}

​

public class TitleResolver : IValueResolver<Item, ItemDetail, string>

{

    public string Resolve(Item source, ItemDetail destination, string destMember, ResolutionContext context)

    {

        if (source != null)

        {

            if (source.BookMetadata != null)

            {

                return source.BookMetadata.Title;

            }

            if (source.MovieMetadata != null)

            {

                return source.MovieMetadata.Title;

            }

        }

        return null;

    }

}

​

public class ItemProfile : Profile

{

    public ItemProfile()

    {

        CreateMap<Item, ItemDetail>()

            .ForMember(dest => dest.Title, opt => opt.MapFrom<TitleResolver>());

    }

}

public class Program

{

    public static void Main()

    {

        //create mapper

        var configuration = new MapperConfiguration(cfg =>

        {

            cfg.AddMaps(typeof(ItemProfile));

        });

        var mapper = configuration.CreateMapper();

        //check if configuration valid

        mapper.ConfigurationProvider.AssertConfigurationIsValid();

        Console.WriteLine("Mapper configuration is valid");

        //try map book metadata

        var bookItem = new Item

        {

            BookMetadata = new BookMetadata()

            {

                Title = "book"

            },

            MovieMetadata = null

        };

        var bookItemDetail = mapper.Map<ItemDetail>(bookItem);

        bool isBookCorrectlyMapped = bookItem.BookMetadata.Title == bookItemDetail.Title;

        Console.WriteLine($"Book mapped correctly: {isBookCorrectlyMapped}");

        //try map movie metadata

        var movieItem = new Item

        {

            BookMetadata = null,

            MovieMetadata = new MovieMetadata()

            {

                Title = "movie"

            }

        };

        var movieItemDetail = mapper.Map<ItemDetail>(movieItem);

        bool isMovieCorrectlyMapped = movieItem.MovieMetadata.Title == movieItemDetail.Title;

        Console.WriteLine($"Movie mapped correctly: {isMovieCorrectlyMapped}");

    }

}