Actualy it doesn't break any encapsulation it's just inheritance Smiley if inheritance breaks encapsulation this does too.

If it is done by the rules of inheritance it does't break encapsulation . It can't.     How?

And btw MyClass<String> it should't be ilegal because String is a sealed class.

so If

class MyClass : string {  // not legal 'String' is sealed class
VS Error :
"Error 1 'Testing.MyClass': cannot derive from sealed type '"

so should be :

MyClass<String> instance; 

I don't see any where your objections are coming from.

I dind't try to sugest a way to break encapsulation but a way to construct a generic type that subclases another type at use time.

And I'm not sugesting any new features or anithing that can't be done with curent language and platform features