C# Generic Class Type parameter (cannot implicitly convert)

Question

Scenario:

class A { }

class B : A { }

class C where T: A { }

Question

Why cant C<

Answer 1

Use co-variant if you need to do this, and because co-variant just work only with interface and delegate, so define an interface with the magic word out instead of class:

interface IC where T : A
{
}

So, you can assign like you want:

class CA : IC
{}

class CB : IC
{ }

IC x = new CA();
IC y = new CB();

x = y;