我怎样才能让我自己的事件在C＃？

How can I make my own event in C#?

感谢

推荐答案

下面是创建和使用的情况下用C＃示例

Here's an example of creating and using an event with C#

using System;

namespace Event_Example
{
    //First we have to define a delegate that acts as a signature for the
    //function that is ultimately called when the event is triggered.
    //You will notice that the second parameter is of MyEventArgs type.
    //This object will contain information about the triggered event.
    public delegate void MyEventHandler(object source, MyEventArgs e);

    //This is a class which describes the event to the class that recieves it.
    //An EventArgs class must always derive from System.EventArgs.
    public class MyEventArgs : EventArgs
    {
    	private string EventInfo;
    	public MyEventArgs(string Text)
    	{
    		EventInfo = Text;
    	}
    	public string GetInfo()
    	{
    		return EventInfo;
    	}
    }

    //This next class is the one which contains an event and triggers it
    //once an action is performed. For example, lets trigger this event
    //once a variable is incremented over a particular value. Notice the
    //event uses the MyEventHandler delegate to create a signature
    //for the called function.
    public class MyClass
    {
    	public event MyEventHandler OnMaximum;
    	private int i;
    	private int Maximum = 10;
    	public int MyValue
    	{
    		get
    		{
    			return i;
    		}
    		set
    		{
    			if(value <= Maximum)
    			{
    				i = value;
    			}
    			else
    			{
    				//To make sure we only trigger the event if a handler is present
    				//we check the event to make sure it's not null.
    				if(OnMaximum != null)
    				{
    					OnMaximum(this, new MyEventArgs("You've entered " +
    						value.ToString() +
    						", but the maximum is " +
    						Maximum.ToString()));
    				}
    			}
    		}
    	}
    }

    class Program
    {
    	//This is the actual method that will be assigned to the event handler
    	//within the above class. This is where we perform an action once the
    	//event has been triggered.
    	static void MaximumReached(object source, MyEventArgs e)
    	{
    		Console.WriteLine(e.GetInfo());
    	}

    	static void Main(string[] args)
    	{
    		//Now lets test the event contained in the above class.
    		MyClass MyObject = new MyClass();
    		MyObject.OnMaximum += new MyEventHandler(MaximumReached);

    		for(int x = 0; x <= 15; x++)
    		{
    			MyObject.MyValue = x;
    		}

    		Console.ReadLine();
    	}
    }
}