Generic class that inherits its generic type [duplicate]

This question already has answers here: Closed 11 years ago.

Possible Duplicates:

Why cannot C# generics derive from one of the generic type parameters like they can in C++ templates?

In C# 4.0, is it possible to derive a class from a generic type parameter?

I'm trying to create a generic class that inherits from its generic type (in 1.Attempt). Looks like it's impossible. But in other attempt i 开发者_如何学Gomust cast the object. Any design solution to that problem?

// #1 Attempt
public interface IFoo { }

public class Generic<T> : T { }

public void play ()
{
    IFoo genfoo = new Generic<IFoo> ();
}

.

// #2 Attempt. Castable solution
public interface IAnything { }

public interface IFoo2 : IAnything { }

public class Generic2<T> : IAnything { }

public void play2 ()
{
    IFoo2 genFoo = (IFoo2) new Generic2<IFoo2> ();
}

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I don't see the point of the code you provided in Attempt #1. Why would you inherit a class and then pass that same class as generic param.

Nevertheless, generic inheritance is supported but its done differently, please check this link, it might give you an idea: Generic Inheritance

Hope this helps.

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What you are doing defeats the generic objective.

How can I just use something like this:

Generic<int> intgen = new Generic<int>(); // Impossible

The problem is generic defines a behaviour which is type-unspecific. your generic is type specific since it has to inherit from it. Generic is used to encapsulate a functionality that cannot be expressed in inheritance while you are mixing the two - and I can tell you it ain't gonna be a good mix.

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You can't do this because T in the definition of the generic is a type definition and not a real class. I'm not sure what you are trying to accomplish, though, because in my opinion your problem could be solved with a simple inheritance. If you are trying to add some behavior to your class then you can simply use a generic and derive from that:

public class Behavior<T>
{
  ...
}

public class DerivedBehavior<T> : Behavior<T>
{
  ...
}