[caseymarquis]

LINQ GroupBy() is the most common use I can think of. I would definitely look into that as it's a nice tool to have. Otherwise, keep them in mind if you're ever pulling data from an external source (SQL, JSON, GQL, Redis, etc) and you're annoyed about having to make a class for some trivial operation.

If a library doesn't have an API for using them with generics, you can paper over that with:

    T fn<T>(T throwAway) => Library.Deserialize<T>();

[to11mtm]

Another example of Anonymous types would be a simple .Select(x=> new {x.ID, x.Name});

Sometimes people lump these in with dynamic objects but those are a very different class of thing indeed.

Now, what would be -really- nice is if we had a way to specify that an anonymous type implements an interface. That could potentially simplify a -lot- of DTO modeling.