本文实例讲述了C#入门教程之集合ArrayList用法。，具体如下：
.NET Framework提供了用于数据存储和检索的专用类，这些类统称集合。这些类提供对堆栈、队列、列表和哈希表的支持。大多数集合类实现系统的接口。下面我们主要来讲一下ArrayList。
ArrayList是命名空间Systrm.Collections下的一部分，它是使用大小可按需动态增加的数组实现IList接口。
ArrayList的容量是ArrayList可以保存的元素数。ArrayList的默认初始容量为0.随着元素添加到ArrayList中，容量会根据需要通过重新分配自动增加。使用证书索引可以访问此集合中的元素。此集合中的索引从零开始。
下面我们先来看一个例子：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections;
namespace 集合{
//动物类
public abstract class Animal
{
protected string name; //动物的名字
public string Name
{
get { return name; }
set { name = value; }
}
public Animal()
{
name="The animal with no name";
}
public Animal(string newName)
{
name=newName;
}
public void Feed() //繁殖后代
{
Console.WriteLine("{0} has been fed.",name);
}
}
//奶牛类
public class Cow : Animal
{
public Cow(string newName): base(newName)
{ }
public void Milk() //产牛奶
{
Console.WriteLine("{0} has been milked.", name);
}
}
//母鸡类
public class Chicken : Animal
{
public Chicken(string newName):base(newName)
{ }
public void LayEgg() //下蛋
{
Console.WriteLine("{0} has laid an egg.", name);
}
}
class Program
{
static void Main(string[] args)
{
//用数组的方法实现
Console.WriteLine("Create an Array type collection of Animal object and use it:");
Animal[] animalArray = new Animal[2];
Cow myCow1 = new Cow("Deirdre");
animalArray[0] = myCow1;
animalArray[1] = new Chicken("Ken");
foreach (Animal myAnimal in animalArray )
{
Console.WriteLine("New {0} object added to Array collection,Name={1}", myAnimal.ToString(), myAnimal.Name);
}
Console.WriteLine("Array collection contains {0} objects.",animalArray .Length );
animalArray[0].Feed();
((Chicken)animalArray[1]).LayEgg();
Console.WriteLine();
//用集合的方法实现
Console.WriteLine("Create an ArrayList type collection of Animal objects and use it;");
ArrayList animalArrayList = new ArrayList();
Cow myCow2 = new Cow("HayLey");
animalArrayList.Add(myCow2);
animalArrayList.Add(new Chicken("Roy"));
foreach (Animal myAnimal in animalArrayList)
{
Console.WriteLine("New {0} object added to ArrayList collection,Name={1}", myAnimal.ToString(), myAnimal.Name);
}
Console.WriteLine("ArrayList collection contains {0} objects.", animalArrayList.Count);
((Animal)animalArrayList[0]).Feed();
((Chicken)animalArrayList[1]).LayEgg();
Console.WriteLine();
}
}
}
