Elegant way to create a nested Dictionary in C#

Question

I realized that I didn\'t give enough information for most people to read my mind and understand all my needs, so I changed this somewhat from the original.

Answer 1

Here's a solution using Linq:

Dictionary> dict = things
    .GroupBy(thing => thing.Foo)
    .ToDictionary(fooGroup => fooGroup.Key,
                  fooGroup => fooGroup.ToDictionary(thing => thing.Bar,
                                                    thing => thing.Baz));