c#中委托补充（实例学习）

实例一:Action委托，以及泛型委托
using System;
using System.Text;
using System.Text.RegularExpressions;

class Test
{
static void Show()
{
Console.WriteLine("打印输出1");
}

private static void Show(int i)
{
Console.WriteLine(i);
}

private static void Show(string str1, string str2)
{
Console.WriteLine(str1+str2);
}

public static void Main()
{
Action a = Show;  //Action为系统内置的一个不带返回值且没有参数的委托
Action<int> a1 = Show;  //Action<T>为一个不带返回值的泛型委托T为参数的类型
Action<string, string> a2=Show;  //带两个参数的委托
a();
a1(1000);
a2("hehe","nihao");
}
}

实例二:Func委托
using System;
using System.Text;
using System.Text.RegularExpressions;

class Test
{
static void Show()
{
Console.WriteLine("打印输出1");
}

private static int Show(int i)
{
Console.WriteLine(i);
return 100;
}

private static string  Show(string str1, string str2)
{
Console.WriteLine(str1+str2);
string str = "完成代码";
return str;
}

public static void Main()
{
Func<int, int> a;    //Func也是系统定义的一个委托，第一个参数为函数参数，第二个参数为返回类型
a = Show;
Func<string, string, string> b;    //能委托的函数带有两个string类型参数，以及一个string类型的返回值
b = Show;
Console.WriteLine(a(1000));
Console.WriteLine(b("代码1","代码2"));
}
}

实例三：多播委托
using System;
using System.Text;
using System.Text.RegularExpressions;

internal class Employ
{
public  int data;
public  string name;

public Employ(int d, string n)
{
data = d;
name = n;
}
}

class Test
{
static void Show()
{
Console.WriteLine("打印输出1");
}

private static void Show2()
{
Console.WriteLine("show2");
}

private static int Show(int i)
{
Console.WriteLine(i);
return 100;
}

private static string  Show(string str1, string str2)
{
Console.WriteLine(str1+str2);
string str = "完成代码";
return str;
}

public static void Main()
{
Action a;
a = Show;
a += Show2;
Delegate[]delegates=a.GetInvocationList();   //多播委托获取所有指向的函数列表
foreach (var v in delegates)
{
v.DynamicInvoke();  //单独调用函数
}
}
}

实例四：使用泛型委托来对类对象排序
using System;
using System.ComponentModel;
using System.Text;
using System.Text.RegularExpressions;

internal class Employ
{
public  int data;
public  string name;

public Employ(int d, string n)
{
data = d;
name = n;
}

public static bool Compare(Employ a, Employ b)   //自定义的比较函数
{
if (a.data > b.data)
return true;
else
{
return false;
}
}

public override string ToString()  //重载原类的ToSting方法,用于输出时直接输出
{
return data + ":" + name;
}
}

internal class Test
{
private static void sort<T>(T [] a,Func<T,T,bool>comp )  //使用泛型委托来实现对对象冒泡排序
{
for (int i = 0; i < a.Length-1; i++)
{
for (int j = 0; j < a.Length-i-1; j++)
{
if (comp(a[j] ,a[j + 1]))   //调用委托
{
T temp = a[j];    //这里其实交换的是数组中的每个对象的引用,相当于c++指针数组中的指针
a[j] = a[j + 1];
a[j + 1] = temp;
}
}
}
}

public static void Main()
{
Employ[] a =
{
new Employ(10, "a"),
new Employ(3, "b"),
new Employ(2, "c"),
new Employ(5, "d"),
new Employ(4, "d")
};
sort<Employ>(a, Employ.Compare);   //调用排序
foreach (var w in a)
{
Console.WriteLine(w);
}
}
}