How can I create a generic function only for a certain class hierarchy?

Question

Can I define a generic method that accepts only an argument only from a certain class hierarchy, the parent and child classes?

void DoSomething(T input) {}

class A {}
class B : A {}

Here I want to use something like:

void DoSomething(A input) {}

and I want this to work also for all cases within the class hierarchy:

A objA;
B objB;

DoSomething(objA);
DoSomething(objB);

user_4728685 · Answer

You can do that by applying a generic constraint for base class

void DoSomething(T input) where T : A
{
}