"ASP is not C."

Please don't tag something as C if it's not within forty-two parsecs of the nearest C compiler.

I've got good news, and I've got bad news:
The universe is merely a figment of my imagination.
Now are you ready for the bad news?

The code snippet populates a checkbox list, which is trivial. The trick is preselecting the checked items and handling onCheckedChanged events. Here is an article that shows how to handle this:
http://forums.asp.net/p/969855/1220533.aspx