Ideally, I'm looking for a templated logical Set class. It would have all of the standard set operations such as Union, Intersection, Etc., and collapse duplicated items.
I ended up creating my own set class based on the C# Dictionary<>- just using the Keys.
No, there is not one natively in the framework. There is an open source implementation that most projects use, (i.e. nHibernate) called Iesi.Collections. Here's a CodeProject article about it:
Matt, +1. That sounds like exactly what he asked for. Looks like that was added long after the codeproject article was written.
I don't think c# has anything built in, but I know there are a couple of implementations floating around on the net. There are also some good articles around on this sort of thing:
This is part 6 of a series on efficiently representing data structure. This part focuses on representing sets in C#.
An implementation of a set collection
An implementation of a set class
Yet another implementation of a set class
And finally...
I've actually used this library myself as the basis of a set implementation that I did a year or so ago.
The best set implementation I have seen is part of the wonderful Wintellect's Power Collections: http://www.codeplex.com/PowerCollections.
The set implementation can be found here:
http://www.codeplex.com/PowerCollections/SourceControl/FileView.aspx?itemId=101886&changeSetId=6259
It has all the expected set operations (union, intersect, etc).
Hope this helps!