實體框架代碼具有自引用實體的第一個存儲庫模式

Question

我試圖在.NET 4.5上爲EF5實現存儲庫/工作單元模式，如下所述：http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/implementing-the-repository-and-unit-of-work-patterns-in-an-asp-net-mvc-application。這一切都很好，直到我嘗試使用如下所述的自引用實體：http://www.codeproject.com/Articles/206410/How-to-Configure-a-Self-Referencing-Entity-in-Code。當我嘗試對包含自引用實體（FieldType）的存儲庫進行任何操作（獲取指定的實體，獲取所有實體，添加實體等）時，我在UnitOfWork類的FieldTypeRepository的getter上得到了一個stackoverflowexception。別擔心，在stackoverflow上發佈stackoverflowexception的諷刺並不會丟失。我已經閱讀了很多關於EF的存儲庫模式的SO文章，但沒有看到任何將它們與自引用實體相結合的文章。

事情我已經嘗試：

• 使用FluentAPI而不是在實體的FieldType屬性 - 無變化
• 直接使用上下文對象 - 這個完美的作品，實體被添加到數據庫，並參考各其他適當的，不幸的失敗存儲庫模式
• 使用存儲庫對非自參考實體的目的 - 適用於.NET 4.0和.NET 4.5大
• 使用EF5 - 同樣的結果

我的代碼：

FieldType.cs

public class FieldType 
{ 
    [Key] 
    [DatabaseGeneratedAttribute(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)] 
    public int FieldTypeId { get; private set; } 

    public string Name { get; set; } 

    public string Description { get; set; } 

    public int? ParentFieldTypeId { get; set; } 

    [ForeignKey("ParentFieldTypeId")] 
    public virtual FieldType ParentFieldType { get; set; } 
} 

UnitOfWork.cs

public class UnitOfWork : IDisposable 
{ 
    private Context context = new Context(); 

    private Repository<FieldType> fieldTypeRepository; 

    public Repository<FieldType> FieldTypeRepository 
    { 
     // EXCEPTION OCCURS HERE 
     get 
     { 
      if (this.fieldTypeRepository == null) 
      { 
       this.fieldTypeRepository = new Repository<FieldType>(this.context); 
      } 

      return this.FieldTypeRepository; 
     } 
    } 

    public void Save() 
    { 
     this.context.SaveChanges(); 
    } 
} 

Context.cs

public class Context : DbContext 
{ 
    public Context() 
     : base("echo") 
    { 
    } 

    public DbSet<FieldType> FieldTypes { get; set; } 
} 

Repository.cs

public class Repository<TEntity> where TEntity : class 
{ 
    private Context context; 

    private DbSet<TEntity> dbSet; 

    public Repository(Context context) 
    { 
     this.context = context; 
     this.dbSet = context.Set<TEntity>(); 
    } 

    public virtual IEnumerable<TEntity> Get(
     Expression<Func<TEntity, bool>> filter = null, 
     Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null, 
     string includedProperties = "") 
    { 
     IQueryable<TEntity> query = this.dbSet; 

     if (filter != null) 
     { 
      query = query.Where(filter); 
     } 

     foreach (var includeProperty in includedProperties.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries)) 
     { 
      query = query.Include(includeProperty); 
     } 

     if (orderBy != null) 
     { 
      return orderBy(query).ToList(); 
     } 
     else 
     { 
      return query.ToList(); 
     } 
    } 

    public virtual TEntity GetById(object id) 
    { 
     return this.dbSet.Find(id); 
    } 

    public virtual void Insert(TEntity entity) 
    { 
     this.dbSet.Add(entity); 
    } 

    public virtual void Delete(object id) 
    { 
     TEntity entityToDelete = this.dbSet.Find(id); 
     this.Delete(entityToDelete); 
    } 

    public virtual void Delete(TEntity entityToDelete) 
    { 
     if (this.context.Entry(entityToDelete).State == EntityState.Detached) 
     { 
      this.dbSet.Attach(entityToDelete); 
     } 

     this.dbSet.Remove(entityToDelete); 
    } 

    public virtual void Update(TEntity entityToUpdate) 
    { 
     this.dbSet.Attach(entityToUpdate); 
     this.context.Entry(entityToUpdate).State = EntityState.Modified; 
    } 
} 

SecurityController.cs（或任何類別真的）

public class SecurityController : Controller 
{ 
    public ActionResult Login() 
    { 
     using (UnitOfWork unitOfWork = new UnitOfWork()) 
     { 
      var fieldType = unitOfWork.FieldTypeRepository.GetById(1); 
      //THIS COULD BE ANY TYPE OPERATION 
     } 

     return this.View(); 
    } 

Answer 1

感謝格特，幫助我意識到，這不是與EF或自引用類型，而是，我是調用get方法有問題對於FieldTypeRepository本身... http://www.youtube.com/watch?v=g6GuEswXOXo