Collections are standard data structures that supplement arrays,
which are the only built-in data structures in C#. In this, C#
differs from languages such as Perl and Python, which incorporate
key/value data structures and dynamically sized arrays into the
The FCL includes a set of types that provide commonly required data
structures and support for creating your own. These types are
typically broken down into two categories: interfaces that define a
standardized set of design patterns for collection classes in
general, and concrete classes that implement these interfaces and
provide a usable range of data structures.
This chapter introduces all the concrete collection classes and
abstract collection interfaces and provides examples of their use.
Unless otherwise stated, the types mentioned in this section all
exist in the System.Collections or
System.Collections.Specialized namespaces, which
are both documented in the reference section of this book, Part V.