Question

if i have a protected method, can i pass in a parameter where the data type is declared internal?

Answer 1

No, unless the type (with the protected member) is itself internal. Internal types cannot be part of a public/protected API, as the consumer would have no way of using it.

You could, however, consider using a public interface to abstract the type – i.e.

public interface IFoo {} internal class Foo : IFoo {} public class Bar {     protected void Test(IFoo foo) {} } 

Generics can be useful for this too:

protected void Test<T>(T foo) where T : IFoo { }