public void WriteText()
 {
     if (txt != null)
     {
         txt.text = "69";
         Debug.Log("69");
     }
     M_EventSystem.UnBind(event_id);
 }
 public void WriteText(string s)
 {
     if (txt != null)
     {
         txt.text = s;
         Debug.Log("666666" + s);
     }
     //M_EventSystem.UnBind<string>(event_id, WriteText);
     //这里完全可以不用传委托进去了的
     M_EventSystem.UnBind(event_id);
 }