How can you inherit from a sealed class using reflection in .Net?

Question

Before you start firing at me, I'm NOT looking to do this, but someone in another post said it was possible. How is it possible? I've never heard of inheriting from anything using reflection. But I've seen some strange things...

Answer 1

Without virtual functions to override, there's not much point in subclassing a sealed class.

If you try write a sealed class with a virtual function in it, you get the following compiler error:

// error CS0549: 'Seal.GetName()' is a new virtual member in sealed class 'Seal' 

However, you can get virtual functions into sealed classes by declaring them in a base class (like this),

public abstract class Animal {     private readonly string m_name;      public virtual string GetName() { return m_name; }      public Animal( string name )     { m_name = name; } }  public sealed class Seal : Animal {     public Seal( string name ) : base(name) {} } 

The problem still remains though, I can't see how you could sneak past the compiler to let you declare a subclass. I tried using IronRuby (ruby is the hackiest of all the hackety languages) but even it wouldn't let me.

The 'sealed' part is embedded into the MSIL, so I'd guess that the CLR itself actually enforces this. You'd have to load the code, dissassemble it, remove the 'sealed' bit, then reassemble it, and load the new version.