Question

I was trying few things and would like to know why this is happening so.

Say, I have a class called A in namespace n and I was trying to create protected internal class B.

namespace n
{
   public class A
   {
      public A()
      {
      }
   }
   protected internal class B //throwing error
   {
   }
}

But when i try like this (B as a sub class of A), its not throwing error and its built success. Could you explain me why it is so?

namespace n
{
   public class A
   {
      public A()
      {
      }
      protected internal class B // its not throwing error
      {
      }
   }      
}

Am i missing anything theoretically? Its quite a bit confusing.

Answer 1

Look at the error.

Elements defined in a namespace cannot be explicitly declared as
private, protected, or protected internal

Only internal or public members are allowed outside the class.

Your second case is defining the class B as member of class A that is why you are not getting the error.

You may see Access Modifiers C#

Classes and structs that are declared directly within a namespace (in
other words, that are not nested within other classes or structs) can
be either public or internal. Internal is the default if no access
modifier is specified.