Automapper映射问题

Question

我需要使用AutoMapper将模型映射到视图模型。

型号：

[Table("News")] 
public class News 
{ 
    [Key] 
    public int Id { get; set; } 
    public string Title { get; set; } 
    public DateTime DatePostedOn { get; set; } 
    public int Position { get; set; } 
    public Category Category { get; set; } 
    public virtual ICollection<Picture> Pictures { get; set; } 
} 

[Table("Pictures")] 
public class Picture 
{ 
    [Key] 
    public int Id { get; set; } 
    public DateTime DateCreated { get; set; } 
    public string Filename { get; set; } 
    public int Type { get; set; } 
    public virtual ICollection<News> News { get; set; } 
} 

视图模型：

public class HomeViewModels 
{ 
    public IList<HomeMainNews> MainNews { get; private set; } 
} 

public class HomeMainNews 
{ 
    public int Id { get; set; } 
    public string Title { get; set; } 
    public string Date { get; set; } 
    public string PictureURL { get; set; } 
} 

映射：

Mapper.CreateMap<News, HomeMainNews>(); 

我该如何映射有一组图片的新闻，在视图模型只有一个图片根据一定条件“Type = 2”

目前的解决方案：

vm.MainNews = db.News 
       .Select(n => new HomeMainNews { 
           Id = n.Id, 
           Date = n.DatePostedOn.ToString(), 
           Title = n.Title, 
           PictureURL = n.Pictures.Where(p => p.Type == 1).Select(p => p.Filename).FirstOrDefault().ToString() 
         }).ToList(); 

Automapper解决方案：

vm.MainNews = db.News.Project().To<HomeMainNews>().ToList(); 

Answer 1

试试这个

Mapper.CreateMap<News, HomeMainNews>() 
      .ForMember(mainNew => mainNew.Date, opt => opt.MapFrom(news => news.DatePostedOn)) 
      .ForMember(mainNew => mainNew.PictureURL, opt => opt.MapFrom(news => news.Pictures.First(pic => pic.Type == 2).Filename));