C# 之 集合ArrayList

.NET Framework提供了用於數據存儲和檢索的專用類，這些類統稱集合。這些類提供對堆棧、隊列、列表和哈希表的支持。大多數集合類實現系統的接口。下面我們主要來講一下ArrayList。

ArrayList是命名空間Systrm.Collections下的一部分，它是使用大小可按需動態增加的數組實現IList接口。

ArrayList的容量是ArrayList可以保存的元素數。ArrayList的默認初始容量為0.隨著元素添加到ArrayList中，容量會根據需要通過重新分配自動增加。使用證書索引可以訪問此集合中的元素。此集合中的索引從零開始。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections;

namespace 集合{

    //動物類
    public abstract class Animal
    {
        protected string name;      //動物的名字

        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()      //繁殖後代
        {
            Console.WriteLine("{0} has been fed.",name);
        }
    }
    //奶牛類
    public class Cow : Animal
    {
        public Cow(string newName): base(newName)
        { }
        public void Milk()      //產牛奶
        {
            Console.WriteLine("{0} has been milked.", name);
        }
    }
    //母雞類
    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)
        {
            //用數組的方法實現
            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();


            //用集合的方法實現
            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();
            
            
            
        }
    }
}

集合的創建<喎?http://www.Bkjia.com/kf/ware/vc/" target="_blank" class="keylink">vc3Ryb25nPjwvcD4KPHA+PHN0cm9uZz48L3N0cm9uZz48L3A+CjxzdHJvbmc+ttTT2rzytaW1xMr91+nAtMu1o6zWu9PQ08O5zLaotcS089ChwLSz9cq8u6/K/dfpo6yyxcTcyrnTw8v8oaM8L3N0cm9uZz48cHJlIGNsYXNzPQ=="brush:java;">Animal[] animalArray = new Aimal[2];
而ArrayList集合不需要初始化其大小

ArrayList animalArrayList = new ArrayList();

Cow myCow2 = new Cow("Hayley");
anmialArrayList.Add(myCow2);
anmialArrayList.Add(new Chicken("Roy"));

foreach (Animal myAnimal in animalArrayList)
{
	Console.WriteLine("New {0} object added to ArrayList collection,Name = {1}",myAnimal.Tostring(),myAnimal.Name);
}

((Animal)animalArrayList[0]).Feed();
((Chichen)animalArrayList[1]).LayEgg();

animalArrayList.RemoveAt(0);
animalArrayList.Remove(myCow2);

animalArrayList.AddRange(animalArray);