Coolest C# LINQ/Lambdas trick you've ever pulled?

Question

Saw a post about hidden features in C# but not a lot of people have written linq/lambdas example so... I wonder...

What\'s the coolest (as in the most

Answer 1

OLINQ reactive LINQ queries over INotifyingCollection - these allow you to do (amongst other things) realtime aggregation against large datasets.

https://github.com/wasabii/OLinq