C# - 具有自定義類型轉換的自動映射器

Question

我正在嘗試向域 map 請求 object，我可以閱讀英語，但我絕對無法在 automapper 文檔中找到解決方案。

問題：

How can I map the ContainedEvent object from source to a derived class in destination object based on the EventType attribute in ContainedEvent object, because Event is an abstract class. So let's say EventType == 1 in the source object, then Event attribute should be converted到它的派生類之一。 我也不想 map null 屬性，但我處理了。

這是請求 object

public class CreatePostRequest
    {

        public long EventTime { get; set; }

        public List<IFormFile>? Pictures { get; set; }

        public ContainedEvent Event { get; set; }

        public virtual List<string>? Tags { get; set; }
    }   

    public class ContainedEvent
    {
        public string Description { get; set; }
        #nullable enable
        public string? Requirements { get; set; }
        public int? Slots { get; set; }
        public double? EntrancePrice { get; set; }
        public int EventType { get; set; }
    }

這是域 object

 public class Post
    {
        public int Id { get; set; }

        public DateTime EventTime { get; set; }

        public Location Location { get; set; }

        public int LocationId { get; set; }

        public AppUser User { get; set; }

        public string UserId { get; set; }

        public Event Event { get; set; }

        public int EventId { get; set; }

        #nullable enable
        public IEnumerable<string>? Pictures { get; set; }

        #nullable enable
        public virtual List<PostTags>? Tags { get; set; }
   }
 public abstract class Event
    {
        public int Id { get; set; }

        public string Description{ get; set; }

        public string? Requirements { get; set; }

        public Post? Post { get; set; }
    }

這就是我所堅持的..

 public class RequestToDomainProfile : Profile
    {
        public RequestToDomainProfile()
        {
             CreateMap<CreatePostRequest, Post>()
                 .ForAllMembers(opt => opt.Condition((src, dest, srcMember) => srcMember != null));

        }
    }

Answer 1

這個想法是將所有 Event 實現存儲在 context.Items 中，並在映射中提供一個選擇器。

沒有測試過，但應該是這樣的

當您創建 map 時：

CreateMap<CreatePostRequest, Post>()
    .ForMember(x => x.Event, opt => opt.MapFrom((src, dest, destMember, context) => 
        { 
            if(src.Event.EventType == 1)
            {
                return context.Items["EventImplementation1"];
            }

            if(src.Event.EventType == 2)
            {
                return context.Items["EventImplementation2"];
            } 

            // ...
        }));

當你 map 你的 object:

Post p = _mapper.Map<CreatePostRequest, Post>(postRequest, opts => 
    { 
        opts.Items["EventImplementation1"] = new YourFirstEventImplementation(); 
        opts.Items["EventImplementation2"] = new YourSecondEventImplementation(); 
        // ...
    });