Why doesn't .Net have a Set data structure?

Question

One of my biggest issues dealing with a move from Java to .Net is the fact that there isn\'t a Set interface in .Net. I know there are libraries I could go and download but

Answer 1

I think it's simply an omission by the BCL writers. .NET 3.5 has a HashSet class; for earlier versions, I recommend wrapping a Dictionary, with nulls in the value field, to replicate O(1) add, remove and lookup time.