Callback List

CallbackList.cs

using System;
using System.Collections.Generic;

using ActionList = System.Collections.Generic.List<System.Action>;
using ActionDict = System.Collections.Generic
    .Dictionary<string, System.Collections.Generic.List<System.Action>>;

// A list of callbacks to easily implement the observable pattern
// Attach to any class as a public static for an easy interface
//
// Foreign classes:
//   Class.callbacks.On("event", _callback);
//
// To trigger:
//   callbacks.RunFor("event");
//
public class CallbackList {
    ActionDict callbacks = new ActionDict();

    public void On(string eventName, Action callback) {
        if (!callbacks.ContainsKey(eventName)) {
            callbacks[eventName] = new ActionList();
        }
        if (callbacks[eventName].IndexOf(callback) != -1) { return; }
        callbacks[eventName].Add(callback);
    }

    public List<Action> For(string eventName) {
        if (!callbacks.ContainsKey(eventName)) {
            return new ActionList();
        }
        return callbacks[eventName];
    }

    public void RunFor(string eventName) {
        if (callbacks.ContainsKey(eventName)) {
            foreach (Action callback in callbacks[eventName]) {
                if (callback != null) { callback(); }
            }
        }
    }

    public void Clear() {
        callbacks.Clear();
    }
}