AdiIRC

I really am missing something here. I tried to assign it to an iDictionary of my own, but I got an error about a missing cast. I tried to use it directly, but it's missing a bunch of methods like TryGetValue. If I try and retrieve a value from it directly, I never get anything back. If I try to retrieve a value from a key that doesn't exist, it doesn't seem to throw an Exception like MSDN says IDictionaries are supposed to.

What am I missing? I'm pretty new to C# (just started using it in November) so I'm obviously missing something simple here, but I'll be darned if I can figure out what.