The System.Collections namespaces contain types that define various standard, specialized, and generic collection objects.
|System.Collections||The System.Collections namespace contains interfaces and classes that define various collections of objects, such as lists, queues, bit arrays, hash tables and dictionaries.|
|System.Collections.Concurrent||The System.Collections.Concurrent namespace provides several thread-safe collection classes that should be used in place of the corresponding types in the System.Collections and System.Collections.Generic namespaces whenever multiple threads are accessing the collection concurrently.|
|System.Collections.Generic||The System.Collections.Generic namespace contains interfaces and classes that define generic collections, which allow users to create strongly typed collections that provide better type safety and performance than non-generic strongly typed collections.|
|System.Collections.ObjectModel||The System.Collections.ObjectModel namespace contains classes that can be used as collections in the object model of a reusable library. Use these classes when properties or methods return collections.|
|System.Collections.Specialized||The System.Collections.Specialized namespace contains specialized and strongly-typed collections; for example, a linked list dictionary, a bit vector, and collections that contain only strings.|