Просто пример простого Comparer-а для сортировок

//Descending Sort, Integer
var queue = new PriorityQueue<int, int>(Comparer<int>.Create((x, y) => y - x));

//Ascending Sort, Object
var queue = new PriorityQueue<ObjectA, ObjectB>(Comparer<ObjectB>.Create((x, y) => x.Something.CompareTo(y.Something));