c# - AutoMapper: 'AutoMapper.AutoMapperMappingException' 类型的异常发生在 AutoMapper.dll 中，但未在用户代码中处理

Question

我有类似 this. 的问题但是这个答案对我不起作用。

我正在做一个小项目。我有两个域模型(Post，Source):

public class Post
{
    public Post()
    {
        Sources = new HashSet<Source>();
    }

    public int Id { get; set; }
    public string Title { get; set; }
    public string About { get; set; }
    public bool IsPublished { get; set; }
    public bool IsFinished { get; set; }
    public DateTime? CreatedOn { get; set; }
    public int? CreatedBy { get; set; }

    public virtual ICollection<Source> Sources { get; set; }
}

public class PostViewModel
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string About { get; set; }
    public bool IsPublished { get; set; }
    public bool IsFinished { get; set; }
    public DateTime? CreatedOn { get; set; }
    public int? CreatedBy { get; set; }

    public virtual ICollection<SourceViewModel> Sources { get; set; }
}   

public ActionResult Edit(int id)
{
    Mapper.CreateMap<Post, PostViewModel>()
        .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id))
        .ForMember(dest => dest.Title, opt => opt.MapFrom(src => src.Title))
        .ForMember(dest => dest.About, opt => opt.MapFrom(src => src.About))
        .ForMember(dest => dest.IsPublished, opt => opt.MapFrom(src => src.IsPublished))
        .ForMember(dest => dest.IsFinished, opt => opt.MapFrom(src => src.IsFinished))
        .ForMember(dest => dest.CreatedOn, opt => opt.MapFrom(src => src.CreatedOn))
        .ForMember(dest => dest.CreatedBy, opt => opt.MapFrom(src => src.CreatedBy))
        .ForMember(dest => dest.Sources, opt => opt.MapFrom(src => src.Sources))
        .ReverseMap();

    var Post = _PostService.Get(id);

    var model = Mapper.Map<Post, PostViewModel>(Post);

    return View(model);
}

但是我收到这样的错误:

An exception of type 'AutoMapper.AutoMapperMappingException' occurred in AutoMapper.dll but was not handled in user code

源域对象和SourceViewModel类似Post和PostViewModel。

希望这能解释我的问题。我该如何解决这个问题？

Answer 1

根据我的经验，最有可能出现问题的是您的资源集合。

当您想使用自动映射器时，最佳做法是显式定义和注册两个实体之间的映射，此外，请确保您已经定义了实体和源子集合的 View 模型之间的映射。