1

我正在尝试在 .NET 4.5 上实现 EF5 的存储库/工作单元模式,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。这一切都很好,直到我尝试使用此处描述的自引用实体:http: //www.codeproject.com/Articles/206410/How-to-Configure-a-Self-Referencing-Entity-in-Code. 当我尝试对包含自引用实体 (FieldType) 的存储库执行任何操作(获取指定实体、获取所有实体、添加实体等)时,我在 UnitOfWork 类中的 FieldTypeRepository 的 getter 上收到 stackoverflowexception。别担心,在 stackoverflow 上发布 stackoverflowexception 的讽刺意味对我来说并没有丢失。我已经阅读了很多关于 EF 存储库模式的 SO 文章,但没有看到任何将它们与自引用实体结合起来的东西。

我尝试过的事情:

  • 使用 FluentAPI 而不是 FieldType 实体上的属性 - 没有变化
  • 直接使用 Context 对象 - 这非常有效,实体被添加到数据库并正确地相互引用,不幸的是这违背了存储库模式的目的
  • 将存储库用于非自引用实体 - 效果很好
  • 将 EF5 用于 .NET 4.0 和 .NET 4.5 - 结果相同

我的代码:

字段类型.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();
    }
}

上下文.cs

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

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

存储库.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(或任何类)

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();
    }
4

1 回答 1

0

感谢 Gert,帮助我意识到这不是 EF 或自引用类型的问题,而是我从自身调用 FieldTypeRepository 的 get 方法... http://www.youtube.com/watch?v= g6GuEswXOXo

于 2013-01-06T23:15:42.433 回答