System.Collections.ArrayList

Added in .NET 1.1

System.Collections.ArrayList

Consider upgrading to System.Collections.Generic.List
Represents a collection of items whose size can be changed dynamically.
These items can have different data types

An arraylist is a combination of an array and a collection.
Unique list of IDs - ArrayList (basically a dynamic single dimensional array)
The ArrayList class fully implements the IList interface with all the familiar methods.
This allows you to work with a set of values as if they were an array and a collection at the same time.
An arraylist has the following functionality:
You can address a value by its index
You can quickly sort and reverse the list
You can search sequentially
You can append elements to the end and insert them in a particular position
You can remove any element
Expands automatically as more elements are added (just like a collection)
Imagine that you need to keep track of various objects but you have no idea how many.
It is difficult to use an array for this purpose because you must declare the size of the array at compile time
The ArrayList is a class designed specifically for this situation
This is an aray whose size is dynamically increased as required.

Does an Element Exist

if (myArrayList.Contains(sElement) == true) 
{ 
}

Converting to a String Array

string[] arValues; 
System.Collections.ArrayList myArrayList; 
arValues = (string[])arArrayList.ToArray(GetType(String))

Methods

Add	Appends an element after the last element in the collection and returns the index where it was inserted.
AddRange
BinarySearch
Clear	Removes all elements from the collection.
Clone
Contains	Returns TRUE if an element exists in the collection.
CopyTo	Copies the elements from the collection to a new one-dimensional array, starting at the specified index in the array.
FixedSize
GetEnumerator	Returns an enumerator to iterate an ArrayList
GetRange
IndexOf	Returns the index of the element in the collection, or -1 if it cannot be found.
Insert	Inserts an element at the specified index.
InsertRange
LastIndexOf
ReadOnly
Remove	Removes an element from the collection
RemoveAt	Removes an element at the specified index from the collection
RemoveRange
Repeat
Reverse	Reverses the order of the elements
SetRange
Sort	Alphabetically sorts the elements
ToArray	Copies all the elements to a new one-dimensional array
TrimToSize

Properties

Capacity	Property contains the number of elements the srray can currently hold.
Count	Returns the number of elements in the collection.
IsFixedSize	Returns TRUE if no more elements can be added to the collection.
IsReadOnly	Returns TRUE is the elements cannot be altered.

Generic Version

The generic version of this collection is System.Collections.Generic.List