HashSet that preserves ordering

Question

I need a HashSet that preserves insertion ordering, are there any implementations of this in the framework?

Answer 1

If you need constant complexity of Add, Remove, Contains and order preservation, then there's no such collection in .NET Framework 4.5.

If you're okay with 3rd party code, take a look at my repository (permissive MIT license): https://github.com/OndrejPetrzilka/Rock.Collections

There's OrderedHashSet collection:

• based on classic HashSet source code (from .NET Core)
• preserves order of insertions and allows manual reordering
• features reversed enumeration
• has same operation complexities as HashSet
• Add and Remove operations are 20% slower compared to HashSet
• consumes 8 more bytes of memory per item