5.2 The class hierarchy for DUIM-Sheets
5.2.2 Subclasses of <event>
Table 5.2 shows the subclasses of the <event> class that are exposed by the DUIM-Sheets library.
<event> |
| ||
<frame-event> | |||
<port-terminated-event> | |||
<timer-event> | |||
<sheet-event> | |||
| <device-event> | See Section 5.2.3 | |
<window-event> | |||
<window-configuration-event> | |||
<window-repaint-event> | |||
The classes of event that are exposed by the DUIM-Sheets library fall into two categories:
- Events that occur in frames: subclasses of the
<frame-event>class - Events that occur in sheets: subclasses of the
<sheet-event>class
Most subclasses of <frame-event> are exposed by the DUIM-Frames library. See Chapter 9, "DUIM-Frames Library", for full details about these subclasses. However, two subclasses of <frame-event> are exposed by the DUIM-Sheets library:
<port-terminated-event>- This class represents the event of a port -- a connection to a display -- being terminated.
<timer-event>This is the class of any event that is timed.
Subclasses of <sheet-event> fall into two categories:
- Device events that occur to devices attached to the computer (typically the keyboard and the pointing device). These are described in Section 5.2.3 on page 205.
- Window events that occur in a window.
Events that occur in a window are subclasses of <window-event>. Two such events are supplied:
<window-configuration-event>- This event occurs whenever the configuration of sheets in a window needs to be recalculated. This may occur in property frames, for example, when clicking on the available tabs to display different pages of information.
- Sometimes, dialog boxes have buttons that allow you to show or hide additional details, which are themselves displayed in an extra pane at the bottom or on the right hand side of the dialog. Clicking on such a button would also create a
<window-configuration-event>, as the additional pane would need to be displayed or hidden, forcing a recalculation of the layout of the sheets in the frame. <window-repaint-event>- This event occurs whenever a region of a window needs to be repainted. This may occur when refreshing a chart or drawing in a frame.