When to use which for?

Question

EDIT Additional options and a slightly extended question below.

Consider this contrived and abstract example of a class body. It demonstrates four different w

Answer 1

As far as performance is concerned I think one of these would work best.

  //A. for
    for (int i = 0; i < someList.Count(); i++)
    {
        someList[i].someAction();
    }

or

 //D. plinq
    someList.AsParallel().ForAll(o => o.someAction());

Although in case of A, I would prefer not to do someList.Count() every time.

for performs better as compared to foreach as far as performance is concerned. D can be better than A but it would depend on the scenario. If you have some large data in somelist, Parallelism might help but if you have small data, it can cause extra burden