Net中委托之三委托的高级应用

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MyDelegateDemo
{
public delegate void SayHelloHandler(string name);//1.委托的声明
public class Greeting
{
public static void SayHello(string name, PeopleType type)
{
if (type == PeopleType.Chinese)
{
Console.WriteLine("早上好,{0}", name);
}
else if (type == PeopleType.American)
{
Console.WriteLine("Good morning,{0}", name);
}
}
/// <summary>
/// 委托，逻辑分离，解除耦合
/// </summary>
/// <param name="name"></param>
/// <param name="sayHello">委托的实例</param>
public static void SayHelloDelegate(string name, SayHelloHandler sayHello)
{
sayHello(name);//委托的调用
}
public static void SayHelloChinese(string name)
{
Console.WriteLine("早上好,{0}", name);
}
public static void SayHelloAmerican(string name)
{
Console.WriteLine("Good morning,{0}", name);
}
}
public enum PeopleType
{
Chinese,
American
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MyDelegateDemo
{
class Program
{

//采用委托易于扩展，对扩展开放，对修改封闭的原则
static void Main(string[] args)
{
Console.WriteLine("欢迎来到流星小子博客学习");
Greeting.SayHello("流星小子", PeopleType.Chinese);
Greeting.SayHello("Meter", PeopleType.American);
//委托的实例化
SayHelloHandler sayHelloHandler = new SayHelloHandler(Greeting.SayHelloChinese);
Greeting.SayHelloDelegate("流星小子", sayHelloHandler);

SayHelloHandler sayHello = new SayHelloHandler(Greeting.SayHelloAmerican);
Greeting.SayHelloDelegate("Meter", sayHello);
//sayHelloHandler -= Greeting.SayHelloChinese;
//sayHelloHandler += Greeting.SayHelloAmerican;
//Greeting.SayHelloDelegate("MeterName", sayHelloHandler);
//sayHelloHandler -= Greeting.SayHelloAmerican;
Console.Read();
}
}
}