Question

我有两个实体，它们之间的关系很多。代码如下：

public class Post : Entity
{
    //public int Id { get; set; }
    public string Title { get; set; }
    public string Body { get; set; }
    public DateTime CreateTime { get; set; }
    public DateTime LastModify { get; set; }

    public ICollection<PostTag> PostTags { get; set; }
    public int AuthorId { get; set; }
    public Author Author { get; set; }
}
public class Tag :Entity
{
    //public int Id { get; set; }
    public string TagName { get; set; }

    public ICollection<PostTag> PostTags { get; set; }
}
public class PostTag :Entity
{
    //public int Id { get; set; }

    public int PostId { get; set; }
    public Post Post { get; set; }
    public int TagId { get; set; }
    public Tag Tag { get; set; }
}
public class PostViewModel
{
    public string Title { get; set; }
    public string Body { get; set; }
    public DateTime CreateTime { get; set; }
    public DateTime LastModify { get; set; }
    public int AuthorId { get; set; }
    public string AuthorName { get; set; }
    public List<TagViewModel> Tags { get; set; }
}

现在，我已经创建了从实体到视图模型的映射配置：

CreateMap<Post, PostViewModel>()
    .ForMember(dest => dest.AuthorId, opt => opt.MapFrom(src => src.Author.Id))
    .ForMember(dest => dest.Tags, opt => opt.MapFrom(src => src.PostTags))
    .ForMember(dest => dest.AuthorName, opt => opt.MapFrom(src => src.Author.User.LastName))
    .ForMember(dest => dest.Body, opt => opt.MapFrom(src => src.Body))
    .ForMember(dest => dest.Title, opt => opt.MapFrom(src => src.Title))
    .ForMember(dest => dest.CreateTime, opt => opt.MapFrom(src => src.CreateTime))
    .ForMember(dest => dest.LastModify, opt => opt.MapFrom(src => src.LastModify))
    .ForMember(dest => dest.Tags, opt => opt.MapFrom(src => src.PostTags.Select(y => y.Tag).ToList()));

我的问题是，当我收到类似PostViewModel的信息时：

public async Task<IActionResult> Post([FromBody] PostViewModel postViewModel)
{

}

如何将PostViewModel映射到Post？我想从PostViewModel创建一个实体，并将它们（即post，tag（如果不存在）和postTag关系）添加到DbContext中，该怎么办？

对于automapper来说我还很陌生，这是我的第一个问题，希望我做对了，我非常感谢您的回答和如何提出要求的指导。

Answer 1

我认为您有两个选择。

1）Reverse mapping

您只需在映射配置的末尾添加.ReverseMap()

CreateMap<Post, PostViewModel>()
    .ForMember(dest => dest.AuthorId, opt => opt.MapFrom(src => src.Author.Id))
    ...
    .ForMember(dest => dest.Tags, opt => opt.MapFrom(src => src.PostTags.Select(y => y.Tag).ToList()))
    .ReverseMap();

2）您可以为PostViewModel至Post定义新的配置

CreateMap<PostViewModel, Post>()
    .ForMember(dest => dest.Author.Id, opt => opt.MapFrom(src => src.AuthorId))
    ...etc

然后Mapper.Map<Post>(postViewModel)

使用自动映射以多对多关系将ViewModel映射到实体

1 个答案: