Cannot map inner navigation property using automapper. EF Core

I have such entities for that particular issue: Album, Photo. Each Album contains a collection of Photos.

And Dto classes: AlbumWithPhotosDto, which contains a collection of PhotoDto.

In my automapper profile I described the mapping rules for all entities:

CreateMap<Photo, PhotoDto>()                  .ForMember(dest => dest.AverageRate, opt => opt.MapFrom(src => src.Ratings.Average(r => r.Rate)))                  .ForMember(dest => dest.RatesCount, opt => opt.MapFrom(src => src.Ratings.Count))                  .ReverseMap();     CreateMap<Album, AlbumWithPhotosDto>()                  .ForMember(dest => dest.PhotosNum, opt => opt.MapFrom(src => src.Photos.Count))                  .ReverseMap();  

Firstly I used LazyLoadingProxies and when I tried to map an Album to an AlbumWithPhotosDto.

I got exception:

Error mapping types.

Mapping types: Album -> AlbumWithPhotosDto DAL.Entities.Album -> BLL.DataTransferObjects.AlbumWithPhotosDto

Type Map configuration: Album -> AlbumWithPhotosDto DAL.Entities.Album -> BLL.DataTransferObjects.AlbumWithPhotosDto

Destination Member: Photos

Then I changed lazy loading on explicit loading such as:

_context.Albums              .Include(a => a.Photos)              .Include(a => a.Author)  

But again I got the same exception. How I can fix this?

Here the additional definitions of classes:

 public class Album : IEntity<int>      {          public int Id { get; set; }          /// <summary>          /// Album name.          /// </summary>          public string Name { get; set; }          /// <summary>          /// Album short description.          /// </summary>          public string Description { get; set; }          /// <summary>          /// Whether the other users can view and rate the album photos or not.          /// </summary>          public bool IsPrivate { get; set; }          /// <summary>          /// Foreign key, creator's id.          /// </summary>          public string AuthorId { get; set; }          /// <summary>          /// User who created the album but not obviously author of all photos.          /// </summary>          public virtual User Author { get; set; }          /// <summary>          /// Photos in album.          /// </summary>          public virtual ICollection<Photo> Photos { get; set; } = new HashSet<Photo>();      }  

public class Photo : IEntity<int>      {          public int Id { get; set; }          /// <summary>          /// Optional photo short description.          /// </summary>          public string Description { get; set; }          /// <summary>          /// Path to the photo file on the hard drive.          /// </summary>          public string FileName { get; set; }          /// <summary>          /// Date and time of uploading.          /// </summary>          public DateTime UploadDate { get; set; }          /// <summary>          /// Photo ratings by users.          /// </summary>          public virtual ICollection<Rating> Ratings { get; set; } = new HashSet<Rating>();          /// <summary>          /// Foreigh key, author's id.          /// </summary>           public string AuthorId { get; set; }          public virtual User Author { get; set; }          public int AlbumId { get; set; }          public virtual Album Album { get; set; }      }  

public class AlbumWithPhotosDto : IDtoMetadata      {          public int Id { get; set; }          public string Description { get; set; }          public string AuthorId { get; set; }          public int PhotosNum { get; set; }          public ICollection<PhotoDto> Photos { get; set; }      }  

public class PhotoDto : IDtoMetadata      {          public int Id { get; set; }          public string Base64 { get; set; }          public string Description { get; set; }          public double AverageRate { get; set; }          public int RatesCount { get; set; }          public DateTime UploadDate { get; set; }          public string AuthorId { get; set; }          public ICollection<RatingDto> Ratings { get; set; }      }  

https://stackoverflow.com/questions/66835624/cannot-map-inner-navigation-property-using-automapper-ef-core March 28, 2021 at 04:08AM