#370 - Subscribe to an Event by Adding an Event Handle

You subscribe to a particular event in C# by defining an event handler-code that will be called whenever the event occurs (is raised). You then attach your event handler to an event on a specific object, using the += operator.

Below is an example where we define an event handler for the Dog.Barked event. Each time that kirby barks, we'll record the date and time of the bark in a list.

 1 private static List<DateTime> barkLog = new List<DateTime>();

 2 

 3 static void Main()

 4 {

 5     Dog kirby = new Dog("Kirby", 12);

 6     kirby.Barked += new EventHandler(kirby_Barked);

 7 

 8     kirby.Bark();

 9     Console.ReadLine();

10 

11     kirby.Bark();

12     Console.ReadLine();

13 }

14 

15 // Neither argument is used, for the moment

16 static void kirby_Barked(object sender, EventArgs e)

17 {

18     // Log kirby's barks

19     barkLog.Add(DateTime.Now);

20 }

Assuming that the Dog class fires its Barked event whenever we call the Bark method, our handler will get called whenever kirby barks.

原文地址：#370 - Subscribe to an Event by Adding an Event Handle