Declares that a class member or interface member has protected visibility.
The protected modifier makes a member of a class or interface visible only within that class or interface and all derived classes of the current class. Code outside the current class cannot access protected members.
Classes and interfaces in the global scope cannot be marked with the protected modifier. Any member of a class or interface (including nested classes and nested interfaces) can be marked with the protected modifier.
You may not combine the protected modifier with any of the other visibility modifiers (public, private, or internal).