我在映射方面遇到问题。这是我的model。
public class Post
{
public int Id { get; set; }
public string Description { get; set; }
public DateTime Created { get; set; }
public User User { get; set; }
public int UserId { get; set; }
}
我的Dto:
public class PostForReturnDto
{
public PostForReturnDto()
{
Created = DateTime.Now;
}
public int Id { get; set; }
public string Description { get; set; }
public DateTime Created { get; set; }
public string Author { get; set; }
}
AutoMapperProfiles.cs
CreateMap<Post, PostForReturnDto>()
.ForMember(p => p.Author,
opt => opt.MapFrom(src => src.User.KnownAs));
RepositoryContext
public async Task<IEnumerable<Post>> GetPosts() {
var posts = _context.Posts
.Include(u => u.User)
.OrderByDescending(p => p.Created)
.ToListAsync();
return await posts;
}
在PostController中处于调试模式时,我在用户对象内部收到以下信息。
我正在尝试将KnownAs属性从User对象映射到我的DTO,但没有成功。错误是:
AutoMapper.AutoMapperMappingException:缺少类型映射配置或不支持的映射。映射类型:List1 -> PostForReturnDto
System.Collections.Generic.List
1 [[DateApp.API.Models.Post,DateApp.API,Version = 1.0.0.0,Culture = neutral,PublicKeyToken = null]]-> DateApp.API.Dtos.PostForReturnDto在lambda_method(Closure,List`1,PostForReturnDto,ResolutionContext)在lambda_method(Closure,Object,Object,ResolutionContext)在C:\ projects \ automapper \ src \ AutoMapper \ Mapper.cs:line 35中的AutoMapper.Mapper.Map [TDestination](对象源)处
似乎您正在映射List<Post>
实例,而不是应该映射的Post
实例
尝试如下
var posts = await _repo.GetPosts();
var res = posts.Select(_ => _mapper.Map<PostToReturn>(_));
return Ok(res);
或者您可以将具有通用参数的集合映射为documentation says
IEnumerable<PostToReturn> postToReturn= mapper.Map<IEnumerable<Post>, IEnumerable<PostToReturn>>(posts);
UPD似乎您的GetPosts()
实现缺少一些Where
或Take
过滤器。它拥有所有职位的权利,如果职位很多,则会在生产中产生性能问题。