unity 3d 使用C#的事件/委托机制

转自：http://blog.youkuaiyun.com/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);  
    }  
      
}