eventbrokerregistrationbyregistrar.html

---
layout: documentation 
title: EventBroker 
teaser: Decoupled eventing with automatic thread switching
navigation:
   - name: Overview
     link: eventbroker.html
   - name: Tutorial
     link: eventbrokertutorial.html	
   - name: Registration by Attribute
     link: eventbrokerregistrationbyattribute.html
   - name: Registration over Interface
     link: eventbrokerregistrationoverinterface.html
   - name: Registration by Registrar
     link: eventbrokerregistrationbyregistrar.html
   - name: Simplified Handler Methods
     link: eventbrokersimplifiedhandlermethods.html
   - name: Direct Interaction
     link: eventbrokerdirectinteraction.html
   - name: Handlers
     link: eventbrokerhandlers.html
   - name: Matchers
     link: eventbrokermatchers.html
   - name: Exception Handling
     link: eventbrokerexceptionhandling.html
   - name: Extensions
     link: eventbrokerextensions.html
   - name: Logging
     link: eventbrokerlogging.html
   - name: Testability
     link: eventbrokertestability.html
   - name: Tips and Tricks
     link: eventbrokertipsandtricks.html
   - name: Specifications
     link: eventbrokerspecifications.html		 
---
<h2>Registration by Event Broker Registrar</h2>
<p>
When your scenario for registering events or event handler methods cannot be achieved with attributes, 
you can use the event broker registrar to register events or handler methods via code.
</p>
<p>
To use the registrar, implement the interface <code>IEventBrokerRegisterable</code> in your publisher or subscriber:
</p>
<script type="syntaxhighlighter" class="brush: csharp"><![CDATA[
public class MyClass : IEventBrokerRegisterable
{
    public event EventHandler Event = delegate { };
	
	public void HandleEvent(object sender, EventArgs eventArgs)
	{ }
	
	public void Register(IEventRegistrar eventRegistrar)
	{
        eventRegistrar.AddPublication(EventTopic, this, ref this.Event);
		
		eventRegistrar.AddSubscription(AnotherEventTopic, this, this.HandleEvent, new OnPublisher());
    }

    public void Unregister(IEventRegistrar eventRegistrar)
    {
	    eventRegistrar.RemovePublication(EventTopic, this, ref this.Event);

        eventRegistrar.RemoveSubscription(AnotherEventTopic, this, this.HandleEvent);
    }
}
]]></script>

<h3>Register Events of the same Class</h3>
<p>
Events of the same class can be registered by using <code>eventRegistrar.AddPublication(...)</code>.
You need to specify the event topic, the instance used as publisher (normally <code>this</code>), the event, the handler restriction 
and optionally publication matchers.
</p>

<h3>Register Event Handler Methods of the same Class</h3>
<p>
Event handler methods of the same class can be registered by using <code>eventRegistrar.AddSubscription(...)</code>.
You need to specify the event topic, the instance used as subscriber (normally <code>this</code>), the event handler method
and optionally subscription matchers.
</p>

<h3>Register Events of other Classes</h3>
<p>
You can register events of other classes by using <code>eventRegistrar.RegisterEvent(...)</code> and specifying
the event topic, the instance to use as the publisher, the name of the event on the class providing the event, 
the handler restriction and optionally publication matchers.
</p>
<p>
This feature is also available directly on the event broker so you don't have to use an intermediate publisher just for adding an event
of another class.
</p>

<h3>Register Event Handler Methods of other Classes</h3>
<p>
You can register event handler methods of other classes by using <code>eventRegistrar.RegisterHandlerMethod(...)</code> and specifying
the event topic, the instance to use as the subscriber, the handler method on the other class and optionally subscription matchers.
</p>
<p>
This feature is also available directly on the event broker so you don't have to use an intermediate subscriber just for adding an event handler method of another class.
</p>

<h3>Register/Unregister additional Instances</h3>
<p>
Use <code>eventRegistrar.Register(object item)</code> and <code>eventRegistrar.Unregister(object item)</code> to register and unregister
additional items - for example private instances of the class - on the event broker.
</p>