In C#, generic collections are collections that enforce strong typing on the elements stored in the collection. Here are some common generic collections in C#:
List<T>
A dynamic array of objects that can be indexed, sorted, and searched. List<T> automatically resizes as elements are added or removed, making it an efficient collection for changing data sets.
Stack<T>
A last-in-first-out (LIFO) collection of objects that supports adding and removing elements at the top of the collection. A stack can be used to reverse the order of elements, or to implement undo functionality in a program.
Queue<T>
A first-in-first-out (FIFO) collection of objects that supports adding elements at the end and removing elements from the front. A queue can be used to implement a task queue or to implement a breadth-first search algorithm.
Dictionary<TKey, TValue>
A collection of key-value pairs that uses a hash code to quickly access elements based on the key. Dictionary<TKey, TValue> is ideal for lookups where the key is used to index the data.
SortedDictionary<TKey, TValue>
A collection of key-value pairs that are sorted by key. SortedDictionary<TKey, TValue> can be used to implement a dictionary with a defined sort order, or to sort elements by key.
HashSet<T>
A collection of unique elements that supports fast lookups, insertions, and deletions. HashSet<T> can be used to implement a set of elements, or to eliminate duplicates from a collection.
LinkedList<T>
A collection of elements that are linked together in a doubly linked list. LinkedList<T> supports inserting and removing elements at any position, and can be used to implement a linked list or a deque.
These collections offer improved type safety and performance compared to non-generic collections, as they enforce strong typing on the elements stored in the collection. Additionally, generic collections can be used with any data type, not just object, making them more flexible and easier to use.