Forbid extension methods
<p>I am publishing a public class as part of my C# framework for users to be able to register within my application. I don't want users to extend my class so I marked it <code>sealed</code>. Now I have some users reporting that they see more methods in that class than the ones I provided. After some investigation, it appeared that these users have defined extension methods that show (by intellisense) just like if they were defined in my public sealed class.</p>

<p><strong>Question</strong>
Is there a way I can forbid users to define extension methods on my public sealed class?</p>
