回调

• Callback , which updates the ui with the state of the
  回调的实现，它用
• The situation arises in the context of callback functions
  这种情况在回调的上下文中发生。
• Wait for the server object to call your callback method
  等待服务器对象调用您的回调方法。
• If the page request is the result of a call back ; otherwise ,
  如果页请求是回调的结果，则为
• The events callbacks usually occur at the time of parsing
  事件回调通常在进行解析时发生。
• Class contains delegates used as referral callback methods
  类包含用作检索回调方法的委托。
• How to : subclass a treeview by using native callbacks
  如何：使用本机回调创建treeview的子类
• Unregisters the message loop callback made with
  发出的消息循环回调。
• Internal pointer that specifies data for the callback method
  指定回调方法数据的内部指针。
• So you need to specify that method in your code as shown in
  属性指定的回调方法。因此需要像