What do people want in a persistent .NET Dictionary?

I've published the PersistentDictionary on Codeplex. This only supports serializing structures, but I will work on a different data structure that supports storing and retrieving arbitrary objects.

https://github.com/microsoft/managedesent

Type restriction may be acceptable on keys, but on values, I'd expect anything that's [Serializable] to work. Otherwise, what's the point? Simple cases like Dictionary<int, string> is seen in textbooks much more often than in real world.