C# classes - Why so many static methods?

Question

I'm pretty new to C# so bear with me.

One of the first things I noticed about C# is that many of the classes are static method heavy. For example...

Why is it:

Array.ForEach(arr, proc)

instead of:

arr.ForEach(proc)

And why is it:

Array.Sort(arr)

instead of:

arr.Sort()

Feel free to point me to some FAQ on the net. If a detailed answer is in some book somewhere, I'd welcome a pointer to that as well. I'm looking for the definitive answer on this, but your speculation is welcome.

Answer 1

Because those are utility classes. The class construction is just a way to group them together, considering there are no free functions in C#.

Answer 2

Assuming this answer is correct, instance methods require additional space in a "method table." Making array methods static may have been an early space-saving decision.

This, along with avoiding the this pointer check that Amitd references, could provide significant performance gains for something as ubiquitous as arrays.