以前，如果我們希望構(gòu)建支持foreach枚舉的自定義集合，只能實(shí)現(xiàn)IEnumerable接口（可能還有IEnumerator()）,返回值還必須是IEnumerator類型，除此之外還可以通過迭代器來使用構(gòu)建foreach循環(huán)的類型，詳細(xì)見下鏈接。
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public class Car { //內(nèi)部狀態(tài)數(shù)據(jù) public int CurentSpeed; public int MaxSpeed; public string name; //汽車能不能用 private bool carIsdead; //類構(gòu)造函數(shù) public Car() { } public Car(string name, int currentspeed, int maxspeed = 100) { this.name = name; this.CurentSpeed = currentspeed; this.MaxSpeed = maxspeed; } //定義委托類型 public delegate void CarEngineHandler(string msdForCar); //定義每個(gè)委托類型的成員變量 private CarEngineHandler listOfhandlers; //向調(diào)用者添加注冊函數(shù) public void RegisterWithCarEngine(CarEngineHandler methodTocall) { if (listOfhandlers == null) listOfhandlers = methodTocall; else listOfhandlers += methodTocall;//支持多路廣播 } //實(shí)現(xiàn)Accelerate()方法 public void Accelerate(int delta) { if (carIsdead) { if (listOfhandlers != null) { listOfhandlers("sorry,this car is dead"); } } else { CurentSpeed += delta; //不能超過最大速度 if (5 == (MaxSpeed - CurentSpeed) && listOfhandlers != null) { listOfhandlers("this speed is nearly to the maxspeed"); } if (CurentSpeed > MaxSpeed) { carIsdead = true; } else Console.WriteLine("current speed:{0}", CurentSpeed); } } } public class Garage : IEnumerable { private Car[] garage = new Car[3]; public Garage() { garage[0] = new Car("a", 10); garage[1] = new Car("b", 13); garage[2] = new Car("c", 14); } public Enumerator GetEnumerator() { //返回?cái)?shù)組對象的IEnumerator //return garage.GetEnumerator(); //用yield關(guān)鍵字構(gòu)建迭代器方法 foreach (Car c in garage) { //當(dāng)yield return語句執(zhí)行后，當(dāng)前位會被 //保存下來，下一次執(zhí)行會從當(dāng)前位開始 yield return c; } } } class Program { static void Main(string[] args) { Garage g = new Garage(); foreach (Car c in g) { Console.WriteLine("car name:{0}", c.name); } } } |
參考：C#中可枚舉類型詳解
以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：http://www.cnblogs.com/janghe/p/7454867.html
