C#基础：高级集合

命名空间System.Collections.ArrayList，实现IList,ICollection,IEnumerable接口，相比数组，可以添加，删除等。

1.  public abstract class Animal//父类，抽象类
2.     {
3.         private string name;
4.         public string Name
5.         {
6.             set { this.name = value; }
7.             get { return this.name; }
8.         }
9.         public Animal() {
10.             this.name = "the animal no name";
11.         }
12.         public Animal(string name) {
13.             this.name = name;
14.         }
15.         public void Feed() => Console.WriteLine($"{name} has been fed");
16.     }
17. //子类继承自Animal
18.  class Chicken:Animal
19.     {
20.         public Chicken(string name) : base(name) { }
21.         public void LayEgg() => Console.WriteLine($"{Name} has been Lay an Egg");
22.     } 
23. //子类继承自Animal
24. class Cow:Animal
25.     {
26.         public Cow(string name) : base(name) { }
27.         public void Milk() => Console.WriteLine($"{Name}has been Milked");

    } 

1. static void Main(string[] args){
2.           
3.            ArrayList animalArrayList = new ArrayList();
4.             Cow myCow2 = new Cow("Rual");
5.             animalArrayList.Add(myCow2);//集合animalArrayList的Add()方法
6.             animalArrayList.Add(new Chicken("Andrea"));
7.             foreach (Animal myAnimal in animalArrayList)//foreach循环输出集合内容
8.             {
9.                 Console.WriteLine($"New{myAnimal.ToString()}" + $" Name={myAnimal.Name}");
10.             }
11.             Console.WriteLine(animalArrayList.Count);//集合的大小，使用Count属性获取.
12.             //多态性
13.             (animalArrayList[0] as Animal).Feed();
14.             ((Cow)animalArrayList[0]).Milk();
15.             ((Chicken)animalArrayList[1]).LayEgg();
16.             Console.WriteLine();
17.             animalArrayList.RemoveAt(0);//集合的RemoveAt()方法
18.             ((Animal)animalArrayList[0]).Feed();
19.             animalArrayList.AddRange(animalArray);//集合的AddRange()方法
20.             ((Chicken)animalArrayList[2]).LayEgg();
21.            //IndexOf()方法（IList接口）
22.             Console.WriteLine($"myCow1的Name={myCow1.Name}" + $" index of {animalArrayList.IndexOf(myCow1)}");
23.             myCow1.Name = "Marry";//修改集合中值的内容
24.             Console.WriteLine($"myCow1的Name={myCow1.Name}" + $" index of {animalArrayList.IndexOf(myCow1)}");
25.  
26.            
27. }