忽略Automapper中從目標到源的屬性？

Question

映射配置文件：

Mapper.CreateMap<Customer, CustomerDto>();
        Mapper.CreateMap<CustomerDto, Customer>();
        Mapper.CreateMap<Movie, MoviesDto>();
        Mapper.CreateMap<MoviesDto, Movie>(MemberList.Source);

Movie課：

namespace Demo3.Models
{
    public class Movie
    {
        public int Id { get; set; }

        [Required(ErrorMessage = "Please Enter Customer Name")]
        [StringLength(255)]
        public string Name { get; set; }

        public Genre Genre { get; set; }

        [Required]
        public byte GenreId { get; set; }

        public DateTime DateAdded { get; set; }
        [Display(Name = "Release Date")]
        public DateTime ReleaseDate { get; set; }

        [Display(Name = "Number In Stock")]
        [Range(1, 20)]
        public byte NumberInStock
        {
            get; set;
        }
    }
}

MoviesDto類：

namespace Demo3.Dtos
{
    public class MoviesDto
    {
        public int Id { get; set; }

        [Required]
        [StringLength(255)]
        public string Name { get; set; }

        [Required]
        public byte GenreId { get; set; }

        public DateTime ReleaseDate { get; set; }

        //public Genre Genre { get; set; }
        [Range(1, 20)]
        public byte NumberInStock
        {
            get; set;
        }
    }
}

例外：

EntityFramework.dll中發生類型'System.InvalidOperationException'的異常，但未在用戶代碼中處理

和

我需要在保存時忽略Genre屬性。

Answer 1

在定義單個屬性映射時（您之所以會幸免，因為它們通過使用相同的名稱自動映射），您必須指定一條忽略指令，如下所示：

Mapper.CreateMap<MoviesDto, Movie>()
      .ForMember(d => d.Genre, o => o.Ignore());