复杂对象/嵌套映射中的自动映射和映射列表

Question

我有一段时间从旧的映射标准转换为automapper。

这是我的课程

// Models
public class BaseModel
{
    public Int64 Id { get; set; }
    public Guid UniqueId { get; set; }
    public DateTime? CreateDate { get; set; }
    public DateTime? LastUpdate { get; set; }
} 

public class LibraryItemModel : BaseModel
{
    public string Name { get; set; }
    public string Description { get; set; }
    public string URL { get; set; }
    public bool IsActive { get; set; }
    public List<LibraryCategoryModel> Categories { get; set; }
}   

public class LibraryCategoryModel : BaseModel
{
    public string Description { get; set; }
}


// Entity Classes

public partial class LibraryItem
{
    public LibraryItem()
    {
        this.LibraryItemCategories = new HashSet<LibraryItemCategory>();
    }

    public long Id { get; set; }
    public System.Guid UniqueId { get; set; }
    public string Description { get; set; }
    public string URL { get; set; }
    public System.DateTime CreateDate { get; set; }
    public System.DateTime LastUpdate { get; set; }
    public bool IsActive { get; set; }
    public string Name { get; set; }

    public virtual ICollection<LibraryItemCategory> LibraryItemCategories { get; set; }
}
// comes from a ternary table in DB... many to many
public partial class LibraryItemCategory
{
    public long LibraryItemId { get; set; }
    public long LibraryCategoryId { get; set; }
    public System.DateTime CreateDate { get; set; }
    public System.DateTime LastUpdate { get; set; }

    public virtual LibraryCategory LibraryCategory { get; set; }
    public virtual LibraryItem LibraryItem { get; set; }
}

public partial class LibraryCategory
{
    public LibraryCategory()
    {
        this.LibraryCategoryRoles = new HashSet<LibraryCategoryRole>();
        this.LibraryItemCategories = new HashSet<LibraryItemCategory>();
    }

    public long id { get; set; }
    public System.Guid UniqueId { get; set; }
    public string Description { get; set; }
    public System.DateTime CreateDate { get; set; }
    public System.DateTime LastUpdate { get; set; }

    public virtual ICollection<LibraryCategoryRole> LibraryCategoryRoles { get; set; }
    public virtual ICollection<LibraryItemCategory> LibraryItemCategories { get; set; }
}


    // Old Conversion code doing it the long way

    private LibraryItemModel Convert(Entities.LibraryItem libraryItem)
    {

        var newLibraryItem = new LibraryItemModel
        {
            UniqueId = libraryItem.UniqueId,
            Name = libraryItem.Name,
            Description = libraryItem.Description,
            URL = libraryItem.URL,
            CreateDate = libraryItem.CreateDate,
            LastUpdate = libraryItem.LastUpdate,
            IsActive = libraryItem.IsActive,
            Categories = new List<LibraryCategoryModel>()
        };

        foreach (var lc in libraryItem.LibraryItemCategories)
        {
            var newCategory = new LibraryCategoryModel
            {
                UniqueId = lc.LibraryCategory.UniqueId,
                Description = lc.LibraryCategory.Description,
                CreateDate = lc.LibraryCategory.CreateDate,
                LastUpdate = lc.LibraryCategory.LastUpdate
            };

            newLibraryItem.Categories.Add(newCategory);
        }

        return newLibraryItem;
    }


    // My attempt at automapper to go between the models and entities
    Mapper.CreateMap<EF.Entities.LibraryItem, LibraryItemModel>();
    Mapper.CreateMap<LibraryItemModel, EF.Entities.LibraryItem>();
          .ForMember(lim => lim.LibraryItemCategories, o => o.Ignore()
    Mapper.CreateMap<EF.Entities.LibraryCategory, LibraryCategoryModel>();
    Mapper.CreateMap<LibraryCategoryModel, EF.Entities.LibraryCategory>()
          .ForMember(lcm => lcm.LibraryCategoryRoles, o => o.Ignore())
          .ForMember(lcm => lcm.LibraryItemCategories, o => o.Ignore());

无论我如何配置忽略或自定义映射，它似乎都不喜欢这种嵌套。 任何Automapper专家都可以告诉我如何使用这样的复杂对象进行映射。 enitity类是通过EF6 edmx文件生成的。

Answer 1

所以基本上这里的问题是，你想从每个地图LibraryItemCategory属于一个LibraryItem到LibraryCategoryModel包括从每个属性LibraryItemCatalog的LibraryCatalog财产。

首先，您要将集合正确映射到彼此：

Mapper.CreateMap<LibraryItem, LibraryItemModel>()
    .ForMember(
        dest => dest.Categories, 
        opt => opt.MapFrom(src => src.LibraryItemCategories));

接下来，你需要担心每个映射LibraryItemCategory内LibraryItem.LibraryItemCategories到LibraryCatalogModel 。 如问题中所述，您需要访问每个LibraryItemCategory的LibraryCatalog属性，并实际上从中映射。 这看起来的方式是：

Mapper.CreateMap<LibraryItemCategory, LibraryCategoryModel>()
    .ConstructUsing(ct => Mapper.Map<LibraryCategoryModel>(ct.LibraryCategory))
    .ForAllMembers(opt => opt.Ignore());

在这里，我们告诉AutoMapper是从映射LibraryItemCategory到LibraryCategoryModel ，我们需要构建LibraryCategoryModel使用另一个调用的Mapper.Map在内LibraryCategory财产。

接下来，剩下要做的就是定义从LibraryCategory到LibraryCategoryModel的映射：

Mapper.CreateMap<LibraryCategory, LibraryCategoryModel>();

现在调用Mapper.Map在LibraryItem应该照顾一切的为您服务。

---

或者，您可以将LibraryItemCategory中的地图移除到LibraryCategoryModel并使用LINQ创建您实际想要从LibraryItem到LibraryItemModel的映射定义中映射的LibraryCategory集合：

Mapper.CreateMap<LibraryItem, LibraryItemModel>()
    .ForMember(
        dest => dest.Categories, 
        opt => opt.MapFrom(
            src => src.LibraryItemCategories.Select(lb => lb.LibraryCategory)));

你显然仍然需要从LibraryCategory到LibraryCategoryViewModel的映射，但你可能更喜欢这个，因为它涉及更少的映射。

Answer 2

尝试类似的东西

Mapper
    .CreateMap<LibraryItemModel, EF.Entities.LibraryItem>()
    .ForMember(
        dest => dest.LibraryItemCategories,
        opt => opt.MapFrom(src => src.LibraryItemCategories )
    );

所以你声明你的嵌套属性将被映射到的位置。

您可以在文档站点上找到另一个示例