Circular Reference + IoC - asp.net-mvc

Question

I have this situation:
Web Project - calling a Business class using Unity 3 IoC. The Web Project doesn't see Business Project. It just references Contracts Project.
namespace Biblioteca.Web.Controllers
{
public class HomeController : Controller
{
public ActionResult Index()
{
return View();
var Autor = Inject.Resolve<IAutorBO>();
}
}
}
Business Project - Here I use the Unity 3 IoC to point to AutorDO class which is in the Data Project (see below). The Business Project doesn't see Data Project.
namespace Biblioteca.Data
{
public sealed partial class AutorBO : IAutorBO
{
#region Atributos
private IAutorDO AutorDO = Inject.Resolve<IAutorDO>();
#endregion
#region Métodos Interface
public IQueryable<DTOAutor> GetAll()
{
return AutorDO.GetAll();
}
public DTOAutor GetById(int id)
{
return AutorDO.GetById(id);
}
void IAutorBO.Insert(DTOAutor dto)
{
AutorDO.Insert(dto);
}
void IAutorBO.Delete(DTOAutor dto)
{
AutorDO.Delete(dto);
}
void IAutorBO.Update(DTOAutor dto)
{
AutorDO.Update(dto);
}
//IQueryable<DTOAutor> IAutorBO.SearchFor(Expression<Func<Autor, bool>> predicate)
//{
// return AutorDO.SearchFor(predicate);
//}
IQueryable<DTOAutor> IAutorBO.GetAll()
{
return AutorDO.GetAll();
}
DTOAutor IAutorBO.GetById(int id)
{
return AutorDO.GetById(id);
}
#endregion
#region Outros Métodos
#endregion
}
}
Data Access Project - Here is my Data Project.
namespace Biblioteca.Data
{
public sealed partial class AutorDO : IAutorDO
{
#region Atributos
Repository<Autor> repository = new Repository<Autor>();
#endregion
#region Implementações Interface
/// <summary>
/// Implementação do método de interface Insert
/// </summary>
/// <param name="dto"></param>
void IAutorDO.Insert(Transport.DTOAutor dto)
{
Autor entity = AssemblerAutor.ToEntity(dto);
repository.Insert(entity);
}
/// <summary>
/// Implementação do método de interface Delete
/// </summary>
/// <param name="dto"></param>
void IAutorDO.Delete(Transport.DTOAutor dto)
{
Autor entity = AssemblerAutor.ToEntity(dto);
repository.Delete(entity);
}
/// <summary>
/// Implementação do método de interface Update
/// </summary>
/// <param name="dto"></param>
void IAutorDO.Update(Transport.DTOAutor dto)
{
Autor entity = AssemblerAutor.ToEntity(dto);
repository.Update(entity);
}
/// <summary>
/// Implementação do método de interface SearchFor
/// </summary>
/// <param name="dto"></param>
/// <returns></returns>
//IQueryable<Transport.DTOAutor> IAutorDO.SearchFor(Expression<Func<Autor, bool>> predicate)
//{
// IQueryable<Autor> list = repository.SearchFor(predicate);
// IQueryable<Transport.DTOAutor> dtoList = (IQueryable<Transport.DTOAutor>)AssemblerAutor.ToDTOs(list);
// return dtoList;
//}
/// <summary>
/// Implementação do método de interface GetAll
/// </summary>
/// <returns></returns>
IQueryable<Transport.DTOAutor> IAutorDO.GetAll()
{
IQueryable<Autor> list = repository.GetAll();
IQueryable<Transport.DTOAutor> dtoList = (IQueryable<Transport.DTOAutor>)AssemblerAutor.ToDTOs(list);
return dtoList;
}
/// <summary>
/// Implementação do método de interface GetById
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
Transport.DTOAutor IAutorDO.GetById(int id)
{
Autor entity = new Autor();
Transport.DTOAutor dto = new Transport.DTOAutor();
using (var ctx = new BibliotecaContext())
{
entity = repository.GetById(id);
dto = AssemblerAutor.ToDTO(entity);
}
return dto;
}
#endregion
}
}
Both Business and Data Projects references the Contracts Project which has all Unity 3 IoC Interfaces, used for implementing IoC. Below are the interfaces used to implement IoC:
namespace Biblioteca.Contracts
{
public interface IAutorBO
{
#region Métodos CRUD
void Insert(DTOAutor dto);
void Delete(DTOAutor dto);
void Update(DTOAutor dto);
//IQueryable<DTOAutor> SearchFor(Expression<Func<Autor, bool>> predicate);
IQueryable<DTOAutor> GetAll();
DTOAutor GetById(int id);
#endregion
}
}
namespace Biblioteca.Contracts
{
public interface IAutorDO
{
#region Métodos CRUD
void Insert(DTOAutor dto);
void Delete(DTOAutor dto);
void Update(DTOAutor dto);
//IQueryable<DTOAutor> SearchFor(Expression<Func<Autor, bool>> predicate);
IQueryable<DTOAutor> GetAll();
DTOAutor GetById(int id);
#endregion
}
}
To complement, I use a generic repository, as below:
namespace Biblioteca.Data
{
/// <summary>
/// Interface para classe genérica para métodos CRUD
/// </summary>
/// <typeparam name="T"></typeparam>
public interface IRepository<T>
{
void Insert(T entity);
void Delete(T entity);
void Update(T entity);
IQueryable<T> SearchFor(Expression<Func<T, bool>> predicate);
IQueryable<T> GetAll();
T GetById(int id);
}
}
namespace Biblioteca.Data
{
/// <summary>
/// Classe genérica para métodos CRUD da camada Data
/// </summary>
/// <typeparam name="T"></typeparam>
public class Repository<T> : IRepository<T> where T : class
{
#region Attributes
protected DbSet<T> dbset;
protected DbContext ctx;
#endregion
#region Constructor
public Repository()
{ }
public Repository(DbContext ctx)
{
this.ctx = ctx;
dbset = ctx.Set<T>();
}
#endregion
#region IRepository<T> Members
public void Insert(T entity)
{
if (dbset.Contains(entity))
{
Update(entity);
}
else
{
dbset.Add(entity);
}
}
public void Delete(T entity)
{
dbset.Remove(entity);
}
public void Update(T entity)
{
using (ctx)
{
ctx.Set<T>().Attach(entity);
ctx.SaveChanges();
}
}
public IQueryable<T> SearchFor(Expression<Func<T, bool>> predicate)
{
return dbset.Where(predicate);
}
public IQueryable<T> GetAll()
{
return dbset;
}
public T GetById(int id)
{
return dbset.Find(id);
}
#endregion
}
}
Notice that I have a commented method in all classes. This Method can not be implemented cause it will cause a circular dependency.
I have the Data Project referencing Contract Project. But I can not use the method "SearchFor" cause it needs the Entity Autor which is in Data Project.
Notice that both Business and Data needs to see Entity classes, cause I have the same method signature.
I need some way to permit use the IoC the way it is, where Web not references Business and Business not references Data, and be able to create other methods where I can pass Entity as parameter.
Any suggestion ? I have already tried to create a third project and points to it but I can't make it works. Is it possible to use Reflection ? If possible, how ?
I will appreciate any suggestion.

Answer 1

If you have a circular dependency, it is a clue you should modify your architecture.
If you need to "have the Data Project referencing Contract Project", then Contract cannot reference Data to get the Entity. You say "Business and Data needs to see Entity classes", so why not keep your entity Autor in an Entities project.
Data
-> references Contract
-> references Entities
Contract
-> references Entities
Or as an alternative, define your entities in the Contract project instead of Data.