Generic repository - IRepository or IRepository

Question

I have seen two different approaches for creating generic repositories. What are differences between those two approaches (pros and cons) ? Please diregard difference in the methods because I am interested in difference between

 public interface IRepository<T> where T : class

and

 public interface IRepository : IDisposable

Is there any difference in functionality, flexibility, unit testing ... ? What will I get or lose ?
Is there any difference how they are registered in Dependency Injection frameworks ?

Option 1

 public interface IRepository<T> where T : class
 {
       T Get(object id);
       void Attach(T entity);
       IQueryable<T> GetAll();
       void Insert(T entity);
       void Delete(T entity);
       void SubmitChanges();
 }

Option 2

 public interface IRepository : IDisposable
    {
        IQueryable<T> GetAll<T>();
        void Delete<T>(T entity);
        void Add<T>(T entity);
        void SaveChanges();
        bool IsDisposed();
    }

score 28 · Accepted Answer · edited Feb 28 '16 at 06:42

28

The biggest difference is that IRepository<T> is bound to a single type while an IRepository is potentially bound to multiple types. Which one is appropriate is highly dependent upon your particular scenario.

Generally speaking I find IRepository<T> to be more useful. At the time of use it's extremely clear what the contents of IRepository<T> are (T). On the other hand it's not clear from a given IRepository what is contained inside of it.

In cases where I have to store multiple types of objects, I usually create a map of IRepository<T> instances. For instance: Dictionary<T,IRepository<T>>.

edited Feb 28 '16 at 06:42

jboeke

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answered Dec 05 '09 at 20:54

JaredPar

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5

When my entities have very different methods I do not recommend implementing IRepository for every entity because every entity will then have a empty implementation of a method which it might not use at all. Do IRepository only if your entities have much common methods else your Repository classes will end up containing empty methods. – msfanboy May 18 '10 at 08:56
3

I don't think an empty method is as dangerous as a giant, world ending solar flair. – ProfK Mar 10 '13 at 10:31

Generic repository - IRepository or IRepository

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