Casting a generic collection to base type

Question

I\'ve got an IList that I want to cast to ICollection but when I attempt an explicit cast, I get null

Answer 1

Switching between generic containers of derived classes and base classes is not supported. (It does work with arrays) It is possible to write a type converter to reasonably cleanly perform the switch without manually copying elements between the lists.

Check out this link for a description of the issue/limitation and a solution: http://www.25hoursaday.com/weblog/CommentView.aspx?guid=AF7AA888-A227-454C-8687-71FA77186064

Down at the bottom is a nice generic-enabled version.