Events are notifications, or messages, that are sent out by AutoCAD® to inform you about the current state of the session, or alert you that something has happened. For example, when a drawing is saved the BeginSave event is triggered. There are other events triggered when a drawing is closed, a command is started or even when a system variable is changed. Given this information you could write a subroutine, or event handler, that uses these events to track changes to a drawing or the amount of time a user spends working on a particular drawing.
事件是 AutoCAD 发出的通知或消息，通知用户有关任务的当前状态，或就发生的某件事警告用户。例如，保存图形时会触发 BeginSave 事件，当打开图形、启动命令以及系统变量被修改时会触发另外的事件。有了这项信息，用户可以编写子例程或事件处理程序，使用这些事件来跟踪处理特定图形所用的时间。
