Chapter 5. Collections

5.0. Introduction

Collections are groups of items; in .NET, collections contain objects, and each object contained in a collection is called an element. Some collections contain a straight-forward list of elements, while others (dictionaries) contain a list of key and value pairs. The following collection types consist of a straightforward list of elements:

	System.Collections.ArrayList
	System.Collections.BitArray
	System.Collections.Queue
	System.Collections.Stack
	System.Collections.Generic.LinkedList<T>
	System.Collections.Generic.List<T>
	System.Collections.Generic.Queue<T>
	System.Collections.Generic.Stack<T>
	System.Collections.Generic.HashSet<T>

The following collection types are dictionaries:

	System.Collections.Hashtable
	System.Collections.SortedList
	System.Collections.Generic.Dictionary<T,U>
	System.Collections.Generic.SortedList<T,U>

The following collection type is a new addition to the .NET Framework Class Library (FCL), which can be thought of as a list of elements with no duplicates:

	System.Collections.Generic.HashSet<T>

These collection classes are organized under the System.Collections and the System. Collections.Generic namespaces. In addition to these namespaces, another name-space called System.Collections.Specialized contains a few more useful collection classes. These classes might not be as well known as the previous classes, so here is a short explanation of the collection classes under the System.Collections.Specialized namespace:

ListDictionary ...

Get C# 3.0 Cookbook, 3rd Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.