委托和事件
委托
委托是一种容器，容器里面放的是函数方法。而函数的形式各不相同，体现在参数、返回值的不同。所以做委托之前，需要定义好委托容器存放函数的类型，即委托类型。定义好委托类型后，将函数加入委托容器后。只要触发委托调用，委托就会将容器中的每个函数都调用一次。
事件
事件在类中声明并生成，且通过使用同一个类或其它类中的委托和事件处理程序关联。包含事件的类用于发布事件，又称发布器类。其它接收该事件的类被称为订阅器类。事件使用发布---订阅模式。
Action委托
.Action说明
- Action是.NET Framework内置的泛型委托，可以使用Action委托以参数形式传递方法，而不用显示声明自定义的委托。封装的方法必须与此委托定义的方法签名相对应。也就是说，封装的方法必须具有一个通过值传递给它的参数，并且不能有返回值。
- Action的特点：参数0-16个，且没有返回值。
Func委托
- Func委托的特点:参数0-16个，必须有返回值
Func委托实战：
实例类：
internal class Student
{
private string name;
private int age;
private int score;
public Student(string name, int age, int score)
{
this.name = name;
this.age = age;
this.score = score;
}
//自我介绍
public void SelfIntroduce()
{
Console.WriteLine("姓名:{0},年龄:{1},分数:{2}",this.name,this.age,this.score);
}
//年龄的比较
public static int AgeCompare(Student firstStudent, Student secondStudent)
{
return firstStudent.age - secondStudent.age;
}
//分数的比较
public static int ScoreCompare(Student firstStudent, Student secondStudent)
{
return firstStudent.score - secondStudent.score;
}
}
测试类
internal class Program
{
static void Main(string[] args)
{
StudentSort();
Console.Read();
}
//冒泡排序的变形
public static void BuBBleSort<T>(T[] array,Func<T,T,int> Compare)
{
for (int i = 0; i < array.Length-1; i++)
{
for (int j = 0; j < array.Length-1-i; j++)
{
if (Compare(array[j], array[j+1])>0)
{
T temp;
temp = array[j];
array[j] = array[j + 1];
array[j+1]= temp;
}
}
}
}
//方法，学生排序
public static void StudentSort()
{
Student student1 = new Student("赵", 18, 90);
Student student2 = new Student("钱", 15, 92);
Student student3 = new Student("孙", 18, 97);
Student student4 = new Student("李", 15, 35);
Student student5 = new Student("周", 18, 40);
Student student6= new Student("吴", 15, 55);
Student student7 = new Student("郑", 18, 10);
Student student8 = new Student("王", 15, 255);
Student[] students= { student1, student2, student3, student4, student5, student6, student7, student8 };
Func<Student, Student, int> funcAge = Student.ScoreCompare;
BuBBleSort(students, funcAge);
foreach (Student student in students)
{
student.SelfIntroduce();
}
}
}
Predicate委托
特点：只允许有一个输入对象，并且会返回bool值。 介绍:表示定义一组条件并确定指定对象是否符合这些条件的方法。 使用场景：检索、判定若干对象中符合条件方法的对象。
实例类
internal class NumJudge
{
//判断目标整数是否为质数
public static bool PrimeJudge(int num)
{
for (int i = 2; i < num-1; i++)
{
if (num % i == 0)
{
return false;
}
}
return true;
}
public static bool EvenJudge(int num)
{
if (num % 2 == 0)
{
return true;
}
return false;
}
}
测试类1，测试数字是否是质数
internal class NumJudge
{
//判断目标整数是否为质数
public static bool PrimeJudge(int num)
{
for (int i = 2; i < num-1; i++)
{
if (num % i == 0)
{
return false;
}
}
return true;
}
static void ShowAllNumber(int startNum, int endNum, Predicate<int> predicate)
{
for (int i = startNum; i <= endNum; i++)
{
if (predicate(i))
{
Console.WriteLine(i);
}
}
}
static void Main(string[] args)
{
// StudentSort();
Predicate<int> pred=NumJudge.PrimeJudge;
ShowAllNumber(1, 100, pred);
Console.Read();
}
测试类2，测试学生数组中的年龄是否等于15，并将其挑选出来
static void StudentPredicate()
{
Student student1 = new Student("赵", 18, 90);
Student student2 = new Student("钱", 15, 92);
Student student3 = new Student("孙", 18, 97);
Student student4 = new Student("李", 15, 35);
Student student5 = new Student("周", 18, 40);
Student student6 = new Student("吴", 15, 55);
Student student7 = new Student("郑", 18, 10);
Student student8 = new Student("王", 15, 255);
Student[] students = { student1, student2, student3, student4, student5, student6, student7, student8 };
//创建委托对象
Predicate<Student> predicate = stu => (stu.age == 15);
//检索学生中满足上述条件的学生
Student[] students1=Array.FindAll<Student>(students, predicate);
foreach (Student student in students1)
{
student.SelfIntroduce();
}
