System.Linq Namespace

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The System.Linq namespace provides classes and interfaces that support queries that use Language-Integrated Query (LINQ).

The Enumerable class contains LINQ standard query operators that operate on objects that implement IEnumerable<T>.

The Queryable class contains LINQ standard query operators that operate on objects that implement IQueryable<T>.

Classes

Class	Description
Public class	Enumerable	Provides a set of static (Shared in Visual Basic) methods for querying objects that implement IEnumerable<T>.
Public class	EnumerableExecutor	Represents an expression tree and provides functionality to execute the expression tree after rewriting it.
Public class	EnumerableExecutor<T>	Infrastructure. Represents an expression tree and provides functionality to execute the expression tree after rewriting it.
Public class	EnumerableQuery	Infrastructure. Represents an IEnumerable as an EnumerableQuery data source.
Public class	EnumerableQuery<T>	Infrastructure. Represents an IEnumerable<T> collection as an IQueryable<T> data source.
Public class	Lookup<TKey, TElement>	Represents a collection of keys each mapped to one or more values.
Public class	Queryable	Provides a set of static (Shared in Visual Basic) methods for querying data structures that implement IQueryable<T>.

Interface	Description
Public interface	IGrouping<TKey, TElement>	Represents a collection of objects that have a common key.
Public interface	ILookup<TKey, TElement>	Defines an indexer, size property, and Boolean search method for data structures that map keys to IEnumerable<T> sequences of values.
Public interface	IOrderedEnumerable<TElement>	Represents a sorted sequence.
Public interface	IOrderedQueryable	Represents the result of a sorting operation.
Public interface	IOrderedQueryable<T>	Represents the result of a sorting operation.
Public interface	IQueryable	Provides functionality to evaluate queries against a specific data source wherein the type of the data is not specified.
Public interface	IQueryable<T>	Provides functionality to evaluate queries against a specific data source wherein the type of the data is known.
Public interface	IQueryProvider	Defines methods to create and execute queries that are described by an IQueryable object.