泛型--List<T>--介绍篇

      System.Collections.Generic命名空间中的List<T>类的用法非常类似于System.Collections命名空间中的ArrayList类。这个类实现了IList、ICollection和IEnumerable接口。下面针对实例来说明如果使用List<T>类。

1. //源代码下载路径：http://media.wiley.com/product_ancillary/41/07645753/DOWNLOAD/Ch10.zip
2. namespace ListDemo
3. {
4.     using System;
5.     using System.Collections.Generic;
6.  
7.     public class Racer
8.     {
9.         private string name;
10.         public string Name
11.         {
12.             get { return name; }
13.         }
14.  
15.         private string car;
16.         public string Car
17.         {
18.             get { return car; }
19.         }
20.  
21.         public Racer(string name, string car)
22.         {
23.             this.name = name;
24.             this.car = car;
25.         }
26.  
27.         public override string ToString()
28.         {
29.             return name;
30.         }
31.     }
32.  
33.     public class Person
34.     {
35.         private string firstname;
36.         public string Firstname
37.         {
38.             get { return firstname; }
39.             set { firstname = value; }
40.         }
41.  
42.         private string lastname;
43.         public string Lastname
44.         {
45.             get { return lastname; }
46.             set { lastname = value; }
47.         }
48.  
49.         public Person(string firstname, string lastname)
50.         {
51.             this.firstname = firstname;
52.             this.lastname = lastname;
53.         }
54.  
55.         public override string ToString()
56.         {
57.             return firstname + " " + lastname;
58.         }
59.     }
60.  
61.     public class FindRacer
62.     {
63.         private string car;
64.         public FindRacer(string car)
65.         {
66.             this.car = car;
67.         }
68.  
69.         /// <summary>
70.         /// 谓词方法--Predicate<T>泛型委托调用的方法
71.         /// public delegate bool Predicate<T>(T obj)--委托定义
72.         /// </summary>
73.         public bool DrivingCarPredicate(Racer racer)
74.         {
75.             return racer.Car == car;
76.         }
77.     }
78.  
79.     public class RacerComparer : IComparer<Racer>
80.     {
81.         public enum CompareType
82.         {
83.             Name,
84.             Car
85.         }
86.  
87.         private CompareType compareType;
88.  
89.         public RacerComparer(CompareType compareType)
90.         {
91.             this.compareType = compareType;
92.         }
93.  
94.         #region IComparer<Racer> Members
95.         public int Compare(Racer x, Racer y)
96.         {
97.             int result = 0;
98.             switch (compareType)
99.             {
100.                 case CompareType.Name:
101.                     result = x.Name.CompareTo(y.Name);
102.                     break;
103.                 case CompareType.Car:
104.                     result = x.Car.CompareTo(y.Car);
105.                     break;
106.             }
107.             return result;
108.         }
109.         #endregion
110.     }
111.  
112.     class Program
113.     {
114.         static void Main(string[] args)
115.         {
116.             //初始化
117.             List<Racer> list = new List<Racer>();                  
118.             //添加对象--这里只能使用Racer类的实例，体现的就是泛型的类型安全
119.             list.Add(new Racer("Michael Schumacher", "Ferrari"));  
120.             list.Add(new Racer("Juan Pablo Montoya", "McLaren-Mercedes"));
121.             list.Add(new Racer("Kimi Raikkonen", "McLaren-Mercedes"));
122.             list.Add(new Racer("Mark Webber", "Williams-BMW"));
123.             list.Add(new Racer("Rubens Barichello", "Ferrari"));
124.  
125.             #region 1、查找元素--FindAll(Predicate<T> match)|执行操作ForEach(Action<T> action)
126.             FindRacer finder = new FindRacer("Ferrari");
127.             //foreach (Racer racer in list.FindAll(new Predicate<Racer>(finder.DrivingCarPredicate)))
128.             //{
129.             //    Console.WriteLine(racer);
130.             //}//和下面的语句执行相同
131.             list.FindAll(new Predicate<Racer>(finder.DrivingCarPredicate))
132.                 .ForEach(delegate(Racer r) { Console.WriteLine(r); });//ForEach方法中使用匿名委托
133.  
134.             //反编译后的FindAll方法
135.             //public List<T> FindAll(Predicate<T> match)
136.             //{
137.             //    if (match == null)
138.             //    {
139.             //        ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
140.             //    }
141.             //    List<T> list = new List<T>();
142.             //    for (int i = 0; i < this._size; i++)
143.             //    {
144.             //        if (match(this._items[i]))
145.             //        {
146.             //            list.Add(this._items[i]);
147.             //        }
148.             //    }
149.             //    return list;
150.             //}
151.             //反编译后的ForEach方法
152.             //public void ForEach(Action<T> action)
153.             //{
154.             //    if (action == null)
155.             //    {
156.             //        ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
157.             //    }
158.             //    for (int i = 0; i < this._size; i++)
159.             //    {
160.             //        action(this._items[i]);
161.             //    }
162.             //}
163.             #endregion
164.  
165.             #region 2、对元素排序Sort(IComparer<T>)|Sort(Comparison<T>)
166.             //使用指定的Comparison<T>【委托】对整个List<T> 中的元素进行排序--这里是匿名委托--返回整数
167.             list.Sort(delegate(Racer r1, Racer r2) { return r1.Name.CompareTo(r2.Name); });
168.             //使用指定的比较器对整个 List<T> 中的元素进行排序。
169.             list.Sort(new RacerComparer(RacerComparer.CompareType.Car));
170.  
171.             Console.WriteLine(""nSorted:");
172.             list.ForEach(delegate(Racer r) { Console.WriteLine(r); });
173.             #endregion
174.  
175.             #region 3、类型转换
176.             List<Person> persons = list.ConvertAll<Person>(delegate(Racer r)
177.             {
178.                 int ixSeperator = r.Name.LastIndexOf(' ') + 1;
179.                 string lastname = r.Name.Substring(ixSeperator, r.Name.Length - ixSeperator);
180.                 string firstname = r.Name.Substring(0, ixSeperator - 1);
181.                 return new Person(firstname, lastname);
182.             });
183.  
184.             Console.WriteLine(""nPersons:");
185.             persons.ForEach(delegate(Person p) { Console.WriteLine(p); });
186.             #endregion
187.  
188.             Console.ReadLine();
189.         }
190.     }
191. }