Generics with Generic Parameters and Abstract class

Question

I\'ve got two generic base classes. The second generic class has a constraint on its parameter of the first class.

abstract class FirstClass {...}
         


        

Answer 1

This is actually an answer to Interface with two generic parameters, solve one automatically which has been marked as duplicate of this question.

You could declare a bunch of interfaces with a specific Id type. Not a perfect solution, but simplifies the declaration of entity classes.

public interface IIntPersistentEntityService
        : IPersistentEntityService
    where TPersistentEntity : IPersistentEntity
{
}

public interface IStringPersistentEntityService
        : IPersistentEntityService
    where TPersistentEntity : IPersistentEntity
{
}

Then the User class can be declared like this:

public class UserService : IIntPersistentEntityService
{
    public User Get(int id)
    {
        throw new NotImplementedException();
    }
}

You will get a compiler error if you have not the matching Id type.