创建通用类C＃

Question

I'm working on a repository for a list of entities, and I should repeat thea same class more than once, the only difference is type type .. is there a way to make it generic?

It should quite easy, for sure I don't know how to make this generic:

 private Namespace.DAL.UserProfileRepository _rep = new Namespace.DAL.UserProfileRepository();

The class I'm repeating it this:

public class UserProfileRepository : IEntityRepository<IUserProfile>
{
   private Namespace.DAL.UserProfileRepository _rep = new Namespace.DAL.UserProfileRepository();

   public IUserProfile[] GetAll()
   {
     return _rep.GetAll();
   }

   public IUserProfile GetById(int id)
   {
     return _rep.GetById(id);
   }

   public IQueryable<IUserProfile> Query(Expression<Func<IUserProfile, bool>> filter)
   {
     return _rep.Query(filter);
   }
}

Answer 1

@NickBray hit the nail on the head. Regardless of how different or similar the actual concrete repository implementations are the DAL class in your example should expose the repository instance via an interface.

Ideally the exposed interface would be declared something like this.

interface IUserProfileRepository : IEntityRepository<IUserProfile>
{
}

This way you could add custom IUserProfile methods as necessary. While the IEntityRepository interface would define the common methods Add , Update , Remove and various QueryXXX methods.

Answer 2

I hope this example helpful for you. If I correctly understood your question, you want to make generizable your repository based on the interface "IEntityRepository".

Try something like this:

    public class UserProfileRepository<TUserProfile> : IEntityRepository<TUserProfile> where TUserProfile : IUserProfile
    {
       private Namespace.DAL.UserProfileRepository _rep = new Namespace.DAL.UserProfileRepository();

       public TUserProfile[] GetAll()
       {
         return _rep.GetAll();
       }

       public TUserProfile GetById(int id)
       {
         return _rep.GetById(id);
       }

       public IQueryable<TUserProfile> Query(Expression<Func<TUserProfile, bool>> filter)
       {
         return _rep.Query(filter);
       }
    }