List of C #

List

Generic collection, which can replace ArrayList

Common methods

ListlistnewList<int>();

Method Name	function
ADD ()	adding elements
AddRange	Add a Collection
ToArray ()	To turn a collection into an array

Array has a method called ToList (), you can turn the array into a set;

Why use list instead of ArrayList

Box packing and unpacking
Converting a value type to a reference type called boxing, converting a reference type to a value type is called unpacking;
Boxing and unpacking are operations at run time, which makes the program run longer, while the generic collection is used to generate the specified type at compile time;
See whether the two types of boxing or unpacking, to see whether the two types of inheritance relationship, there is an inheritance relationship is possible to occur boxing operations;

class name	element Type	whether a unboxing occurred	Run Time
List	Determined and unique	Whether	relatively short
ArrayList	Not sure, but there are many kinds of	Is	Long time

usingSystem;usingSystem.Collections;usingSystem.Collections.Generic;usingSystem.Diagnostics;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespaceList Generic Collection {classprogram {Static voidMain (string[] args) {ArrayListList=NewArrayList ();//arraylist Program time: 00:00:00.1229805            //list Program time: 00:00:00.0276141            //list<int> List = new list<int> ();            List. ADD (0);List. ADD (0); Console.WriteLine (List.            Count); Stopwatch SW =NewStopwatch (); Sw. Start (); for(inti =0; I <1000000; i++) {List.            ADD (i); } SW.            Stop (); Console.WriteLine ("program Time:"+SW.            Elapsed);        Console.readkey (); }    }}

List of C #