- static Provides a set of static (Shared in Visual Basic) methods for querying objects that implement IEnumerable`1.
- Represents a collection of keys each mapped to one or more values.
- Represents a collection of objects that have a common key.
- Defines an indexer, size property, and Boolean search method for data structures that map keys to IEnumerable`1 sequences of values.
- Represents a sorted sequence.