unity 3d 使用C#的事件/委托机制

转自：http://blog.csdn.net/hiramtan/article/details/8955472

事件分发：

using UnityEngine;
public class EventDispatcher : MonoBehaviour {
public delegate void EventHandler(GameObject e);
public event EventHandler MouseOver;
void OnMouseOver () {
if (MouseOver != null)
MouseOver (this.gameObject);
}
}

事件监听：

private GameObject s;
[...]
s.GetComponent<EventDispatcher>().MouseOver += Listener;
[...]
void Listener(GameObject g) {
// g is being hovered, do something...
}

结束监听某个事件：

s.GetComponent<EventDispatcher>().MouseOver -= Listener;

一个通用的EventDispatcher类，实现所有GameObject能够分发的事件。

using UnityEngine;
using System.Collections;

/**
*  A simple event dispatcher - allows to listen to events in one GameObject from another GameObject
*
*  Author: Bartek Drozdz (bartek [at] everyday3d [dot] com)
*
*  Usage:
*  Add this script to the object that is supposed to dispatch events.
*  In another objects follow this pattern to register as listener at intercept events:

void Start () {
EventDispatcher ev = GameObject.Find("someObject").GetComponent<EventDispatcher>();
ev.MouseDown += ListeningFunction; // Register the listener (and experience the beauty of overloaded operators!)
}

void ListeningFunction (GameObject e) {
e.transform.Rotate(20, 0, 0); // 'e' is the game object that dispatched the event
e.GetComponent<EventDispatcher>().MouseDown -= ListeningFunction; // Remove the listener
}

*  This class does not implement all standards events, nor does it allow dispatching custom events,
*  but you shold have no problem adding all the other methods.
*/
public class EventDispatcher : MonoBehaviour
{

public delegate void EventHandler (GameObject e);
public delegate void CollisionHandler (GameObject e, Collision c);

public event EventHandler MouseOver;
void OnMouseOver ()
{
if (MouseOver != null)
MouseOver (this.gameObject);
}

public event EventHandler MouseDown;
void OnMouseDown ()
{
if (MouseDown != null)
MouseDown (this.gameObject);
}

public event EventHandler MouseEnter;
void OnMouseEnter ()
{
if (MouseEnter != null)
MouseEnter (this.gameObject);
}

public event EventHandler MouseExit;
void OnMouseExit ()
{
if (MouseExit != null)
MouseExit (this.gameObject);
}

public event EventHandler BecameVisible;
void OnBecameVisible ()
{
if (BecameVisible != null)
BecameVisible (this.gameObject);
}

public event EventHandler BecameInvisible;
void OnBecameInvisible ()
{
if (BecameInvisible != null)
BecameInvisible (this.gameObject);
}

public event CollisionHandler CollisionEnter;
void OnCollisionEnter (Collision c)
{
if (CollisionEnter != null)
CollisionEnter (this.gameObject, c);
}

public event CollisionHandler CollisionExit;
void OnCollisionExit (Collision c)
{
if (CollisionExit != null)
CollisionExit (this.gameObject, c);
}

}