What is an internal sealed class in C#?

Question

I was looking through some C# code for extending language support in VS2010 (Ook example). I saw some classes called internal sealed class

What do these do?

Answer 1

• internal: A class which can only be accessed inside the same assembly.

  Assembly1.dll:

  namespace test {
      internal class InternalClass {
      }
  
      public class PublicClass { 
      }
  } 
  

  Assembly2.dll:

  using test;
  ...
  InternalClass c1; // Error
  PublicClass c2; // OK
  

• sealed: A class which cannot be derived from

  sealed class SealedClass { ... }
  
  class ChildClass : SealedClass {} //ERROR