C#委托事件

来源：互联网发布：unity3d模型百度云编辑：程序博客网时间：2024/06/15 05:03

示例1：

1、定义类，人，英国人，中国人

public class people

{
public delegate void delGreate(string msg,string opera);
public event delGreate eGreate;
public void Greate(string msg,string opera)
{
if(eGreate!=null)
{
eGreate(msg,opera);
}
}
}

public class englishPeople
{
people pe;
public englishPeople(people p)
{
pe = p;
pe.eGreate += GreateEng;
}

public void GreateEng(string msg, string opera)
{
if(opera.Contains("english"))
{
Console.WriteLine("英语问候：" + msg);
}
}
}

public class chinaPeople
{
people pe;
public chinaPeople(people p)
{
pe = p;
pe.eGreate += GreateChina;
}
public void GreateChina(string msg,string opera)
{
if(opera.Contains("china"))
{
Console.WriteLine("汉语问候：" + msg);
}
}

}

2、调用

people peo = new people();
englishPeople eng = new englishPeople(peo);
chinaPeople chi = new chinaPeople(peo);
peo.Greate("张三","english");
Console.ReadKey();

示例2：

Action<T> 委托

using System;
using System.Windows.Forms;
 
delegate void DisplayMessage(string message);
 
public class TestCustomDelegate
{
   public static void Main()
   {
      DisplayMessage messageTarget; 
 
      if (Environment.GetCommandLineArgs().Length > 1)
         messageTarget = ShowWindowsMessage;
      else
         messageTarget = Console.WriteLine;
 
      messageTarget("Hello, World!");  
   }     
 
   private static void ShowWindowsMessage(string message)
   {
      MessageBox.Show(message);     
   }
}
以下简化了此代码，它所用的方法是实例化 Action<T> 委托，而不是显式定义一个新委托并将命名方法分配给该委托。
using System;
using System.Windows.Forms;
 
public class TestAction1
{
   public static void Main()
   {
      Action<string> messageTarget; 
 
      if (Environment.GetCommandLineArgs().Length > 1)
         messageTarget = ShowWindowsMessage;
      else
         messageTarget = Console.WriteLine;
 
      messageTarget("Hello, World!");  
   }     
 
   private static void ShowWindowsMessage(string message)
   {
      MessageBox.Show(message);     
   }
}
也可以将 Action<T> 委托与匿名方法一起使用。

using System;

using System.Windows.Forms;

public class TestLambdaExpression

{

   public static void Main()

{

      Action<string> messageTarget; 

      if (Environment.GetCommandLineArgs().Length > 1)

         messageTarget = a => ShowWindowsMessage(s); 

      else

         messageTarget = a => Console.WriteLine(s);

      messageTarget("Hello, World!");

}

   private static void ShowWindowsMessage(string message)

{

      MessageBox.Show(message);  

}

}

阅读全文

0 0