C# Dictionary<> and mutable keys

Question

I was told that one of the many reasons strings were made immutable in the C# spec was to avoid the issue of HashTables having keys changed when references to the string key

Answer 1

The Dictionary<> class does nothing to protect itself against a mutable key object being changed. It's up to you to know whether or not the class you're using as a key is mutable, and to avoid it if possible.