Collections

Collections means the process of which the objects are handled by your program.it holds a set of classes to have elements in a generalized form.By using collections,you can perform Various operations on objects like the store,search,sort,retrieve, update,delete etc.

Types of collections

There are following types of classes in collection, here are shown below.

System.Collections.Generic Classes

In this classes we use System.Collections.Generic namespace.These Collections are used for type-compatible with the type of collections for items that are stored in generic collection.This collection have set of interfaces and classes. here we show classes that are used in System.Collections.Generic namespace.

List	List is used for resized dynamically i.e dynamic array.it is accessed by index and this class represents the list of objects.
LinkedList	It is used to fast removing and inserting of elements.it uses enumerators.
Dictionary	It is used to store key/value pairs.it used the same functionality that is used in non-generic hashtable class.
Queue	It use first-in,first-out list.it's functionality similar to that occur in non-generic queue class.
HashSet	It is used to prevent duplication in the collection.it is an collection of the unique elements in unordered form.
SortedList	it uses the functionality similar to that occur in non-generic sortedlist class.it is key/value pair of sorted list.
Stack	it uses First-in,last-out list.

System.Collections Classes

In this Non-Generic collection we use System.Collections namespace. it is not used for type-compatible with the type of collections for items.It can handle any type of objects.This collection have set of interfaces and classes. here we show classes that are used in System.Collections namespace.

ArrayList	ArrayList means size of array is dynamic not fixed.it's size increase and decrease at runtime.
Queue	Queue shows first-in,first-out collection of objects.you can use in first-in,first-out access of items.
Hashtable	Hashtable shows collection of key/value pairs.it is based on hash code of the key.
Stack	stack is used last-in,first-out pattern(LIFO pattern) for input/output.

System.Collections.Concurrent Classes

In this collections multiple threads are accessing the collection simultaneously.it gives several threads-safe collection classes that are used in System.Collections.Concurrent namespace. This collection came in dot net framework version 4 and onwards.