导航属性的包含是否可以使用EF6嵌套在Web API中？

Question

从我Web API使用generic-repository/uow模式的服务开始EF6,我需要返回嵌套的导航属性.模型A具有模型B,模型B具有模型C等.像这样的东西:

public class A
    {
        public int SomeID { get; set; }
        public ICollection<B> Bs { get; set; }
    }    
public class B
    {
        public int SomeID { get; set; }
        public ICollection<C> Cs { get; set; }
    }

我可以在A中获得B,但是B中的C是空的.这就是我这样做的方式:

// GENERIC REPOSITORY
public IQueryable<TEntity> Get(params Expression<Func<TEntity, object>>[] includes)
        {
            IQueryable<TEntity> query = _dbSet;
            if (includes != null)
            {
                foreach (var include in includes)
                    query = query.Include(include);
            }
            return query;
        }
//  FROM THE "A" CONTROLLER
public HttpResponseMessage Get()
        {
            HttpResponseMessage response;
            var results = _unitOfWork.A_Repository.Get(s => s.Bs);
            if (results == null)
            {
                response = new HttpResponseMessage(HttpStatusCode.NotFound);
            }
            else
            {
                response = Request.CreateResponse(HttpStatusCode.OK, results);
            }
            return response;
        }

我不知道如何从A控制器传递额外的lambdas以获得B中加载的Cs.我可以看到如何在不使用通用存储库的情况下执行此操作.我也愿意使用OData,但无法弄清楚如何在Web API中使用此模式

我也尝试使用DbContext方法并失败:

public class MyContext : DbContext
    {
        public DbSet<A> As { get; set; }
        public DbSet<B> Bs { get; set; }
        public DbSet<C> Cs { get; set; }

        public MyContext()
            : base("MyDBContext")
        {
        }    
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<B>().HasRequired(i => i.C);
            Bs.Include(i => i.C);
        }
    }

Answer 1

您可以使用单个Include呼叫执行此操作

_context.A_Repository // where to get from
    .Include(a => a.Bs.Select(b => b.Cs.Ds.Es)) // what to include
    .Where(a => a.IsCool == true) // how to filter
    .ToList(); // materialize result

请参阅EntityFramework文档的备注.