This post is another in a series that will just contain little GUCs (Generic Utility Classes) I’ve developed along the way. If these already exist as part of the framework and I’ve overlooked them, feel free to let me know! And if you know of a better way to implement them, do the same! I’m never too old to learn something new (I hope!). I've blogged in the past about how useful the overlooked HashSet class can be (here) and about the very useful ToDictionary() extension method. This post introduces an extension method I wrote and use in some of my work that turns an IEnumerable into a HashSet.