In GUI programming we often want a change in one widget to be notified to another widget.
In GUI programming we often want a change in one widget to be notified to another widget.
在图形用户界面编程中，我们常常希望一个窗口接收到其他窗口的通知之时做出改变。
In GUI programming we often want a change in one widget to be notified to another widget.
在图形用户界面编程中，我们常常希望一个窗口接收到其他窗口的通知之时做出改变。