将多个DTO添加到单个实体的通用存储库（Automapper）

Question

我在一个项目中工作，我有一个通用的服务和存储库层。我正在使用Automapper将DTO映射到实体模型。一个实体可以有一个或多个DTO。我的问题是，如何告诉我的通用存储库类哪个DTO应该返回到服务层？

实体

[Table("Entity")]
public class Entity
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int id { get; set; }

    [Required]
    public string name { get; set; }

    [Required]
    public string surname { get; set; }
}

DTOs

public class Contract
{
}

[DataContract]
public class EntityContract: Contract
{
    [Required]
    [DataMember]
    public string name { get; set; }

    [Required]
    [DataMember]
    public string surname { get; set; }
}

[DataContract]
public class EntityPassportContract: Contract
{
    [Required]
    [DataMember]
    public string name { get; set; }

    [Required]
    [DataMember]
    public string surname { get; set; }

    [Required]
    [DataMember]
    public string passport { get; set; }
}

通用存储库

public interface IGenericRepository<E, DTO> 
    where E : class
    where DTO: class
{
    List<DTO> findBy(Expression<Func<DTO, bool>> query = null, Func<IQueryable<DTO>, IOrderedQueryable<DTO>> orderBy = null,
                                Expression<Func<DTO, bool>> whereIn = null, int? page = null, int? sizePage = null);
}

通用存储库实现

public abstract class GenericRepository<C, E, DTO> : IGenericRepository<T, DTO> 
    where E : class
    where DTO: class
    where C : IdentityDbContext<User>, new()
{
    //...
    public virtual List<DTO> findBy(Expression<Func<DTO, bool>> query = null, Func<IQueryable<DTO>, IOrderedQueryable<DTO>> orderBy = null,
                                        Expression<Func<DTO, bool>> whereIn = null, int? page = null, int? sizePage = null)
    {
        //...transform DTO queries to E queries and Get IQueriable<E> entity from database
        DTO dtoEntity=entity.ProjectTo<DTO>();
        return dtoEntity;                           
    }
}

通用服务

public interface IService<E, DTO> : IService
    where T: class
    where DTO: class
{
    List<DTO> findBy(Expression<Func<DTO, bool>> query = null, Func<IQueryable<DTO>, IOrderedQueryable<DTO>> orderBy = null,
                                           Expression<Func<DTO, bool>> whereIn = null, int? page = null, int? sizePage = null);
}

通用服务实现

public abstract class Service<E, DTO> : IService<T, DTO>
    where E: class
    where DTO: class
{

    protected IGenericRepository<E, DTO> repository;
    public Service(IGenericRepository<E, DTO> repository,)
    {
        this.repository = repository;
    }
    public virtual List<DTO> findBy(Expression<Func<DTO, bool>> query = null, Func<IQueryable<DTO>, IOrderedQueryable<DTO>> orderBy = null,
                                               Expression<Func<DTO, bool>> whereIn = null, int? page = null, int? sizePage = null)
    {
        return repository.findBy(query, orderBy, whereIn, page, sizePage).ToList();
    }
}

实体存储库和服务

public interface IEntityRepository : IGenericRepository<Entity, Contract>
{
}
public class EntityRepository : GenericRepository<EntitiesDB, Entity, Contract>, IEntityRepository
{
    public EntityRepository(IMapper mapper):base(mapper){ }
}

//Service
public interface IEntityService : IService<Entity, Contract>
{
}
public class EntityService : Service<Entity, Contract>, IEntityService
{
    private IEntityRepository repo;

    public EntityService(IEntityRepository repo) : base(repo)
    {
        this.repo = repo;
    }
}

控制器我想在泛型服务中调用findBy方法，并选择要返回的DTO。合同类是我测试的一部分，但它不起作用。我是否必须使用反射将服务中的每个方法传递给我想要的数据类型？

[RoutePrefix("api/entity")]
public class EntityController : ApiController
{
    public EntityController(IEntityService entityService)
    : base(entityService)
    {
    }
    [Route("getEntityByFilter", Name = "getEntityByFilter")]
    [HttpGet]
    public async Task<IHttpActionResult> getEntityContract(string filter)
    {
        EntityContract entityContract=entityService.findBy(**Parameters**); //Need to call lambda expressions here so i think i need somehow the type.
        return Ok(entityContract);
    }
    [Route("getEntityByFilter2", Name = "getEntityByFilter2")]
    [HttpGet]
    public async Task<IHttpActionResult> getEntityPassportContract(string filter)
    {
        EntityPassportContract entityPassportContract=entityService.findBy(**Parameters**); //Need to call lambda expressions here so i think i need somehow the type.
        return Ok(entityPassportContract);
    }
}

非常感谢提前！我希望这个问题也能帮助其他人！

祝你周末愉快！

卢西亚诺

Answer 1

对不起，我的回答耽搁了，但不管怎样，给你。

我发现这样做的方法是告诉方法我想要返回哪个实体。所以，我的存储库是这样的

public abstract class GenericRepository<C, E> : IGenericRepository<T> 
where E : class
where C : IdentityDbContext<User>, new()
{
    //...
    public virtual List<DTO> findBy<DTO>(Expression<Func<DTO, bool>> query = 
     null, Func<IQueryable<DTO>, IOrderedQueryable<DTO>> orderBy = null,
                                    Expression<Func<DTO, bool>> whereIn = 
      null, int? page = null, int? sizePage = null)
    {
        //...transform DTO queries to E queries and Get IQueriable<E> entity 
           from database
        DTO dtoEntity=entity.ProjectTo<DTO>();
        return dtoEntity;                           
    }
}

所以现在，每次我必须调用存储库时，我都在服务类中这样调用它：

//If I want the EntityListResumeDTO
List<EntityListResumeDTO> EntityListContract = repo.findBy<EntityListResumeDTO>(x=>x.id==1);

//If I want the EntityListCompleteDTO
List<EntityListCompleteDTO> EntityListContract = repo.findBy<EntityListCompleteDTO>(x=>x.id==1);

如您所见，DTO泛型类型不再是类级别的，而是方法级别的。

希望这能帮助其他人，如果你有更好的解决方案，请让我知道。

干杯