System.Collections.Generic.List

Added in .NET 2.0
Represents a collection of objects that can be individually accessed by an index
Appending elements is fast but inserting elements at a given position is slow
Searching using binary search is fast if the list has already been sorted.
This type of collection represents a collection on keys and values
provides access by index numbers

System.Collections.Generic.List 

Fixed Size

Allows modification of elements but does not allow the addition or removal of elements.

myList = new System.Collections.Generic.List<string>(3); 
myList.Add("one"); 
myList.Add("two"); 
myList.Add("three"); 
System.Diagnostics.Debug.Print System.String.Format("Count={0}", myList.Count) 

System.Diagnostics.Debug.Print myList[2]; 

Variable Size

Allows addition, removal and modification of elements.

Where

GenericList.Add = how to check of its already been added ? 

Distinct

GenericList.Distinct.ToList 

ToArray

copy the list to an array

get a value at a given index
get a subrange/sublist between 2 index positions

reverse the order of the items

get an enumerator for the list