如何使用存储库模式急切加载子实体

Question

我有一个名为的实体Tour可以有很多Agents.我可以添加代理,但我无法删除它们.

// _repo is injected....
var tour = _repo.GetById(tourId);
tour.AddAgent(new Agent(tour.TourId));

当我尝试调用该Tour.RemoveAgent()方法时,实际上没有删除任何内容.我在Tour.RemoveAgent()方法中设置了一个断点,我看到该_agents属性的计数为0.

tour.RemoveAgent(agentId); // This doesn't work because _agents is empty

_agents当我Tour从我的存储库中检索时,是否必须为EF填充属性做一些特殊操作？

更新:解决问题(感谢Paul的回答)

我决定只为每个聚合创建一个唯一的存储库,这样就可以很容易地定义使用该Include()函数需要包含的内容.这是我从GenericRepository<T>类继承的一个例子(它也包含在这个问题的底部).

public class TourRepository : GenericRepository<Tour>
{
    public TourRepository(IDatabaseFactory databaseFactory) : base (databaseFactory)
    {
    }

    public override Tour GetById(Guid id)
    {
        return dataContext.Tours
                .Include(x => x.Agents)
                .Single(x => x.TourId == id);
    }
}

旅游类

public partial class Tour
{
  public Guid TourId { get; private set; }
  protected virtual List<Agent> _agents { get; set; }

  public Tour()
  {
    TourId = Guid.NewGuid();
    _agents = new List<Agent>();
  }

  public void AddAgent(Agent agent)
  {
    _agents.Add(agent);
  }

  public void RemoveAgent(Guid agentId)
  {
    _agents.RemoveAll(a => a.AgentId == agentId);
  }
}

代理类

public partial class Agent
{
  public Guid AgentId { get; private set; }
  public Guid TourId { get; private set; }
  public Tour Tour { get; private set; }

  public Agent(Guid tourId)
  {
    TourId = tourId;
    AgentId = Guid.NewGuid();
  }
}

OnModelCreating

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
  // AGENTS ============================
  modelBuilder.Entity<Agent>()
              .HasKey(x => x.AgentId)
              .Property(p => p.AgentId);

  modelBuilder.Entity<Agent>()
              .HasRequired(p => p.Tour)
              .WithMany(t => t.Agents);

  // TOURS =============================
  modelBuilder.Entity<Tour>()
              .HasKey(x => x.TourId)
              .Property(x => x.TourId);
}

存储库类

public class GenericRepository<T> : IRepository<T> where T : class {
  private MyContext dataContext;
  private readonly IDbSet<T> dbset;  

  public GenericRepository(IDatabaseFactory databaseFactory)
  {
    DatabaseFactory = databaseFactory;
    dbset = DataContext.Set<T>();
  }

  protected IDatabaseFactory DatabaseFactory
  {
    get;
    private set;
  }

  protected MyContext DataContext
  {
    get { return dataContext ?? (dataContext = DatabaseFactory.Get()); }
  }

  // ... stuff removed for brevity ...

  public T GetById(Guid id)
  {
    return dbset.Find(id);
  }
}

Answer 1

尝试制作受保护的虚拟列表_agents {get; 组; } 上市

public virtual List<Agent> _agents { get; set; }

你也可以通过这样做来急切加载:

_databaseContext.Tours.Include(x => x.Agents).Single(x => x.TourId == tourId) 

你可以在这里阅读更多内容:http://blogs.msdn.com/b/adonet/archive/2011/01/31/using-dbcontext-in-ef-feature-ctp5-part-6-loading-related-entities. ASPX