Why isn't there a ConcurrentList<T>

Question

The new namespace System.Collections.Concurrent contains concurrent collections for dictionary, queue and stack among other classes. Anyone know why is it that there is no ConcurrentList?

UPDATE

I've posted a new question explaining my current scenario. I preferred that to changing the whole sense of the original question. Here's the link to the new question.

Answer 1

Random access doesn't make much sense on a data structure that's changed from another thread.

If you look at the concurrent collections, you'll notice that their interface is specifically designed to work well with multi threaded access. I can't think of a useful list-like interface that works well with multithreaded code.

Random multi threaded access can make sense if the elements are never moved, but then you have an array.

Answer 2

If two threads added items simultaneously what expectation of 'order' would you have? ConcurrentBag is more appropriate if all you want is a collection of items.

Answer 3

Back in 2011 I wrote a ConcurrentList<T> class (code available on GitHub), which is thread-safe, lock-free, and implements some of the IList<T> interface.

Notably, any operations that mutate the list other than Add are not supported; i.e., it is an append-only collection. So Insert, RemoveAt, etc. don't work.