using System;
using System.Collections.Generic;
using System.Text;
namespace delegateTest
{
/// <summary>
/// 演示利用委托给不同类型的对象排序
/// </summary>
class Program
{
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)
static void Main(string[] args)
{
Employee[] employees = {
new Employee("Bugs Bunny",20000),
new Employee("Elmer Fudd",10000),
new Employee("Daffy Duck",25000),
new Employee("Wiley Coyote",(decimal)1000000.38),
new Employee("Foghorn Leghorn",23000),
new Employee("Road Runner",50000)
};
CompareOp c1 = new CompareOp(Employee.CompareEmploySalary);
BubbleSorter.Sort(employees, c1);//对employees数组,按工资高低排序
for (int i = 0; i < employees.Length; i++)
{
Console.WriteLine(employees[i].ToString());
}
Console.WriteLine("---------------------------------------");
object[] ints = { 3, 5, 2, 8, 6, 0 };
c1 = new CompareOp(CompareInt);
BubbleSorter.Sort(ints, c1);//对ints数组,按数值大小排序
for (int i = 0; i < ints.Length; i++)
{
Console.WriteLine(ints[i].ToString());
}
Console.WriteLine("---------------------------------------");
Console.ReadLine();
}
/// <summary>
/// 比较整数的大小
/// </summary>
/// <param name="x">整数1</param>
/// <param name="y">整数2</param>
/// <returns>如果第一个数小于第二数,返回true,反之false</returns>
static bool CompareInt(object x, object y)
{
return (int)y>(int)x?true:false;
}
/// <summary>
/// 冒泡排序类
/// </summary>
class BubbleSorter
{
static public void Sort(object[] sortArray, CompareOp gtMethod)
{
for (int i = 0; i < sortArray.Length; i++)
{
for (int j = i + 1; j < sortArray.Length; j++)
{
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
{
object temp = sortArray[i];
sortArray[i] = sortArray[j];
sortArray[j] = temp;
}
}
}
}
}
}
/// <summary>
/// 员工实体类
/// </summary>
class Employee
{
private string name;
private decimal salary;
/// <summary>
/// Employee构造函数
/// </summary>
/// <param name="name"></param>
/// <param name="salary"></param>
public Employee(string name, decimal salary)
{
this.name = name;
this.salary = salary;
}
/// <summary>
/// 覆盖ToString()方法
/// </summary>
/// <returns></returns>
public override string ToString()
{
return string.Format(name + ",{0:c}", salary);
}
/// <summary>
/// 按员工工资高低比较大小
/// </summary>
/// <param name="lhs"></param>
/// <param name="rhs"></param>
/// <returns></returns>
public static bool CompareEmploySalary(object lhs, object rhs)
{
Employee empLhs = (Employee)lhs;
Employee empRhs = (Employee)rhs;
return (empRhs.salary > empLhs.salary) ? true : false;
}
}
}
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
---------------------------------------
0
2
3
5
6
8
---------------------------------------