Are typed ArrayLists a good idea?
I love ArrayLists. I find them to be among the most useful collections in the .NET Framework. I remember seeing a discussion somewhere a few months ago about making ArrayLists into strongly-typed collections. This was achieved by simply inheriting ArrayList and overriding the Add/Insert methods to make sure the objects being added were a particular type.
I don't know enough about what's going on under the hood to know if there's a performance penalty involved with this. Is checking the type of an object an expensive process?