UGTK / Toolkit / Utility Systems / Event System Completed

Event System

Summary

The Event System lets objects talk to each other by name, without holding references. A controller owns a pool of event objects; you activate one under a name, anybody subscribes to that name, anybody invokes it. Sender and receiver never need to know about each other, and neither has to exist when the other is wired up.

The event objects are pooled, so creating and dropping events during play does not allocate.

Only the zero-parameter event is usable today. Mn_Event_OneParameters<T> and Mn_Event_TwoParameters<T,T1> exist in the code but ship with no controller and no prefab: to use them you have to write the controller yourself.

Content

• Modules Dependencies
• Setup
• How To Use
• Testing Scene
• Technical Info

Modules Dependencies

• Pooling System: the controller takes its event objects from a pooler instead of instantiating them.

Setup

A single event. Drop the EventZeroParameters prefab into the scene:

Give it a name — this is the key everything else will use, and setting it also renames the GameObject:

Then wire the listeners from the inspector, exactly like a UnityEvent:

A controller, when events are created and destroyed at runtime. Drop the ZeroParametersController prefab:

Optionally associate its Animator, so an animation can raise the events by name:

The custom inspector can activate, deactivate and invoke events while playing, so the wiring can be checked without writing any calling code:

How To Use

Mn_ZeroParametersController events;

events.ActiveNewEvent("DoorOpened");                     // take one from the pool under this name
events.SubScribeToEvent("DoorOpened", myListener);       // note the capital S in "SubScribe"
events.InvokeEvent("DoorOpened");
events.UnSubscribeToEvent("DoorOpened", myListener);
events.DeactiveEvent("DoorOpened");                      // give it back to the pool

On a single Mn_Event_ZeroParameters you can also call AddListener / RemoveListener / Invoke directly, plus ActiveEvent / DeactiveEvent and GetName / SetName.

Good to know:

• ⚠️ The method is SubScribeToEvent, with a capital S in the middle. Its counterpart is spelled normally, UnSubscribeToEvent. Autocomplete will not find the first one if you type Subscribe.
• An inactive event swallows the invoke silently. Invoke() checks the active flag and returns without doing anything: an event you forgot to activate — or that you already deactivated — fails quietly, with no warning. This is the first thing to check when "the event does not fire".
• The name is the contract. Nothing checks it: a typo in InvokeEvent raises nothing and reports nothing. Keep the names in constants rather than in string literals scattered around.
• ActiveNewEvent really does take a new one from the pool: calling it twice with the same name gives you two distinct events sharing that name, and the lookup returns the first. Activate once.
• SetName renames the GameObject too, so events are easy to find in the Hierarchy while debugging.
• Deactivating returns the object to the pool: its listeners are gone with it, and re-activating the same name gives you a clean event. Do not expect the subscriptions to survive.

Testing Scene

Open Debug/EventSceneExample.unity: EventUserExample subscribes to an event and reacts to it, so you can watch the whole activate → subscribe → invoke cycle in the console.

Technical Info

• Back to the toolkit index

© 2026 Marcello De Bonis. All rights reserved

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