Hooking Generic Repository With IOC container

I am trying to create a generic repository pattern where i can swtich ORM technogies , But i stumbled upon this problem when trying to hook with IOC container

 public interface IRepository<T>  
 {
      //members
 }

For NHbernate this works fine

public class FNHRepository<T>: IRepository<T> 
{ //members }

But for Entity i am forced to add where clause

public class EFRepository<T> : IRepository<T> where T : class 
{

if i am omiting the "where clause" i am not able to do

dbset = DataContext.Set<T>() ; 

saying only reference type can be used as T

The problem comes when i am trying to hook IRepository with an IOC , like this

.RegisterType(typeof(IRepository<>), typeof(EFRepository<>)); 

I am not able to hook the interface if the implemeting class is having where T : class 开发者_运维技巧, I am getting the following execption

xception is: InvalidOperationException - The current type, System.Web.Mvc.IControllerFactory, is an interface and cannot be constructed. Are you missing a type mapping?

Any help appriciated , i tried this with Unity and Autofac and getting the same error

Not sure about Unity, but you should be able to register a generic class with constraints just fine.

builder.RegisterGeneric(typeof(EFRepo...))
    .AsImplementedInterfaces();

The problem though is this: without the same constraint on the interface, this is bound to fail:

container.Resolve<IRepo<int>>();