using System;

using AutoMapper;

using System.Collections.Generic;

public class Program

{

    public static void Main() {

        var mapper = new Mapper(new MapperConfiguration(cfg => {

            cfg.CreateMap<PostTag, TagDto>()

                .ForMember(d => d.Name, o => o.MapFrom(s => s.Tag.Name));

​

            cfg.CreateMap<Post, PostDto>()

                .ForMember(d=> d.PostTags, o=>o.MapFrom(s=>s.PostTag));

        }));

        var posts = new List<Post> {

            new Post {Title = "Post1", PostTag = new List<PostTag>{new PostTag{Tag = new Tag{Name="tag1"}}}},

            new Post {Title = "Post2", PostTag = new List<PostTag>{new PostTag{Tag = new Tag{Name="tag2"}}}},

        };

​

        var postDtos = mapper.Map<List<PostDto>>(posts);

        postDtos.Dump();

    }

​

    // Entities

    public class Post {

        public string Title { get; set; }

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

    }

    public class Tag {

        public string Name { get; set; }

        public List<PostTag> PostTags { get; set; }

    }

    public class PostTag {

        public Post Post { get; set; }

        public Tag Tag { get; set; }

    }

    // DTOs

    public class PostDto {

        public string Title { get; set; }

        public List<TagDto> PostTags { get; set; }

    }

    public class TagDto {

        public string Name { get; set; }

    }

}