>>那是不是就意味着DialogBox函数内部有一个消息循环？
DialogBox内部是不是有一个消息循环不好说,肯定的一点是系统提供了modal dialog 键盘接口,而非模态对话框则不是.这一点在MSDN 上有说明:(Dialog Box Keyboard Interface)
The system automatically provides the keyboard interface for all modal dialog boxes.
It does not provide the interface for modeless dialog boxes unless the application
calls the IsDialogMessage function to filter messages in its main message loop. This
means that the application must pass the message to IsDialogMessage immediately
after retrieving the message from the message queue. The function processes
the messages if it is for the dialog box and returns a nonzero value to indicate
that the message has been processed and must not be passed to the TranslateMessage or DispatchMessage function.
