Tutorial: Harnessing the power of EventSink

[wieganka]

Well, I've seen several people lately ask about how they can do things when players login, etc, so, I've decided to put together a very quick tutorial on using EventSink.

Q: What is the EventSink Class?
A: The EventSink Class is a class that gives you the ability to "subscribe" to specific events that happen in the game.

Q: Subscribe? Huh?
A: Think of it as subscribing to your local newspaper. Every morning (or whenever the newspaper is delivered), you get a newspaper at your door. In effect, you are "informed" of this "event", and can take action on it. This may sound strange, but It'll make sense later.

Q: OK, enough talk, show me!
A: Alright, scroll down below for a sample EventSink class.

using Server;
 
namespace Server.Misc
{
   public class EventSinkTest
   {
        public static void Initialize()
       {
           EventSink.Login += new LoginEventHandler(EventSink_Login);
           EventSink.PlayerDeath += new PlayerDeathEventHandler(EventSink_PlayerDeath);
           EventSink.Logout += new LogoutEventHandler(EventSink_Logout);
       }
 
        public static void EventSink_Login(LoginEventArgs e)
       {
            //Broadcast a message to everyone
           World.Broadcast(0x35, true, string.Format("{0} just logged in.", e.Mobile.Name));
       }
 
        public static void EventSink_Logout(LogoutEventArgs e)
       {
            //Broadcast a message to everyone
           World.Broadcast(0x35, true, string.Format("{0} just logged out.", e.Mobile.Name));
       }
 
        public static void EventSink_PlayerDeath(PlayerDeathEventArgs e)
       {
            //Auto resurrect
           e.Mobile.Resurrect();
           e.Mobile.Hits = e.Mobile.HitsMax;
           e.Mobile.Stam = e.Mobile.StamMax;
           e.Mobile.Mana = e.Mobile.ManaMax;
       }
   }
}

OK, so we created a class, and called it EventSinkTest. In that class, we have the following:

public static void Initialize()

This code is run when the class gets loaded by RunUO, so you don't actually have to call this to get your code to run. Inside this procedure, lets look at the first line:

EventSink.Login += new LoginEventHandler(EventSink_Login);

This line is doing the actual "subscribing". This is basically adding your callback function to the stack of callbacks that get run when a player logs into the shard. If you were to use "-=" instead of the "+=", you would "unsubscribe" your callback....but that's a different topic, so I won't go into depth on that.

Now that you have the subscription setup, you need the procedure call:

public static void EventSink_Login(LoginEventArgs e)
{
}

That is the code that will be called now when a player logs in. You can do just about anything in here. I just do a simple World.Broadcast, just to exemplify what can be done.

That is the end of this tutorial...yes it's small, but I wanted to try and make this as easy as possible. Poke around the EventSink class to find out other events that you can subscribe to. Also, take a look at the other 2 EventSinks that I use in this class.

Good luck, and happy coding!