Is it possible to make a parameter implement two interfaces?

Question

Is it possible to define a function that takes in a parameter that must implement two interfaces?

(The two interfaces are ones I just remembered off the top of my head; not the ones I want to use)

private void DoSomthing(IComparable, ICollection input) {  } 

Answer 1

You can:

1) Define an interface that inherits both required interfaces:

public interface ICombinedInterface : IComparable, ICollection {... }  private void DoSomething(ICombinedInterface input) {... } 

2) Use generics:

private void DoSomething<T>(T input)     where T : IComparable, ICollection {...} 

Answer 2

You can inherit another interface from those two interfaces and make your parameter implement that interface.