Question

I started to implement a repository pattern following this tutorial. Now In the definition of the class which implements the interface of Repository. The defines of the classes are made like this.

public class Repository<E,C> : IRepository<E,C>, IDisposable 
    where E : EntityObject
    where C : ObjectContext
{
}

Can someone explain me if I defined a class with generics why do i need to type where to explain which are the objects that are expected??. I’m really confused with this topic

Answer 1

Constraining the types with where is a deliberate choice, which has two consequences:

1. The compiler will not allow you to write code that instantiates the generic if the type parameters do not satisfy these constraints, and in return
2. It will allow you to use objects of class E and C as EntityObject and ObjectContext within the definition of Repository<,>; otherwise, it would not let you access members (methods, properties, etc) of those classes because it wouldn’t be able to guarantee that those members exist on the types used to specify the generic.