1using System;
2using System.Collections.Generic;
3using System.Text;
4
5namespace delegateTest
6{
7 /// <summary>
8 /// 演示利用委托给不同类型的对象排序
9 /// </summary>
10 class Program
11 {
12 delegate bool CompareOp(object lhs,object rhs);//声明委托(注意方法签名的格式是两个object类型参数)
13
14 static void Main(string[] args)
15 {
16 Employee[] employees = {
17 new Employee("Bugs Bunny",20000),
18 new Employee("Elmer Fudd",10000),
19 new Employee("Daffy Duck",25000),
20 new Employee("Wiley Coyote",(decimal)1000000.38),
21 new Employee("Foghorn Leghorn",23000),
22 new Employee("Road Runner",50000)
23 };
24
25 CompareOp c1 = new CompareOp(Employee.CompareEmploySalary);
26
27 BubbleSorter.Sort(employees, c1);//对employees数组，按工资高低排序
28
29 for (int i = 0; i < employees.Length; i++)
30 {
31 Console.WriteLine(employees[i].ToString());
32 }
33
34 Console.WriteLine("---------------------------------------");
35
36 object[] ints = { 3, 5, 2, 8, 6, 0 };
37
38 c1 = new CompareOp(CompareInt);
39 BubbleSorter.Sort(ints, c1);//对ints数组，按数值大小排序
40 for (int i = 0; i < ints.Length; i++)
41 {
42 Console.WriteLine(ints[i].ToString());
43 }
44
45 Console.WriteLine("---------------------------------------");
46
47 Console.ReadLine();
48 }
49
50 /// <summary>
51 /// 比较整数的大小
52 /// </summary>
53 /// <param name="x">整数1</param>
54 /// <param name="y">整数2</param>
55 /// <returns>如果第一个数小于第二数,返回true,反之false</returns>
56 static bool CompareInt(object x, object y)
57 {
58 return (int)y>(int)x?true:false;
59 }
60
61 /// <summary>
62 /// 冒泡排序类
63 /// </summary>
64 class BubbleSorter
65 {
66 static public void Sort(object[] sortArray, CompareOp gtMethod)
67 {
68 for (int i = 0; i < sortArray.Length; i++)
69 {
70 for (int j = i + 1; j < sortArray.Length; j++)
71 {
72 if (gtMethod(sortArray[j], sortArray[i])) //比较大小，注:不同的object,比较大小的方法不同,
//比如Employee是按工资高低来比较,int是按数字大小来比较,
//利用委托的好处就在于不用管具体用哪种方法,
//具体调用的时候才确定用哪种方法
73 {
74 object temp = sortArray[i];
75 sortArray[i] = sortArray[j];
76 sortArray[j] = temp;
77 }
78 }
79
80 }
81 }
82 }
83 }
84
85
86 /// <summary>
87 /// 员工实体类
88 /// </summary>
89 class Employee
90 {
91 private string name;
92 private decimal salary;
93
94
95 /// <summary>
96 /// Employee构造函数
97 /// </summary>
98 /// <param name="name"></param>
99 /// <param name="salary"></param>
100 public Employee(string name, decimal salary)
101 {
102 this.name = name;
103 this.salary = salary;
104 }
105
106 /// <summary>
107 /// 覆盖ToString()方法
108 /// </summary>
109 /// <returns></returns>
110 public override string ToString()
111 {
112 return string.Format(name + ",{0:c}", salary);
113 }
114
115 /// <summary>
116 /// 按员工工资高低比较大小
117 /// </summary>
118 /// <param name="lhs"></param>
119 /// <param name="rhs"></param>
120 /// <returns></returns>
121 public static bool CompareEmploySalary(object lhs, object rhs)
122 {
123 Employee empLhs = (Employee)lhs;
124 Employee empRhs = (Employee)rhs;
125 return (empRhs.salary > empLhs.salary) ? true : false;
126 }
127 }
128}运行结果:
Elmer Fudd,￥10,000.00
Bugs Bunny,￥20,000.00
Foghorn Leghorn,￥23,000.00
Daffy Duck,￥25,000.00
Road Runner,￥50,000.00
Wiley Coyote,￥1,000,000.38
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