A PriorityQueue is a list that always keeps its items sorted based on some rule, like smallest to largest. So, when you take an item out, you always get the one with the highest (or lowest) priority.

Using Lists as Stacks and Queues. You can create lists that function as stacks (first in, last out lists) or queues (first in, first out lists). ... As with stacks, you should use the ITEMTYPE and ...

The ConcurrentStack and ConcurrentQueue classes, lock-free and thread-safe implementations of the Stack and Queue classes, build thread safe collections in .Net ...