Comment by withinboredom

C# is a follower of DDD, mostly. Which is a 'standard' practice for OOP design. I highly recommend reading the book about it, but that is how you end up with many classes instead of a simple function. Also, in C#, you can't generally mock a function (or static method?, not 100% sure on that, it's been nearly 10 years since I've written a unit test in C#).