Introduction to PowerBuilder
Menu Guidelines
You have seen the mechanics behind menu creation, let's look at some of the implications of using custom menus in your application. You should be aware of these implications because, as opposed to adding functionality you might be adding holes to your application. The following list documents some of the important points concerning the creation of custom menus for your application:
- If the currently active sheet doesn't have it's own menu, then the menu and the toolbar associated with the last active sheet remains in place and operative for the whole time the sheet is active. If the currently active sheet has a menu but no toolbar, the previous toolbar would still be displayed.
- Menu toolbars only work in MDI frame and MDI sheet type of windows. If you open a non-MDI window with a menu that has a toolbar, the toolbar won't be shown.
- Menu toolbar buttons map directly to menu items, so clicking a menu toolbar button is same as clicking its corresponding menu item.
- Disabling a menu item will disable its toolbar button as well, but won't change the appearance of the button.
- Hiding a menu item doesn't cause DropDown or Cascading menu item toolbar buttons to disappear. However, it does disable them by graying out of the button.
- Hiding an item on a DropDown or Cascading menu doesn't cause its toolbar button to disappear or to be disabled.
- A double toolbar effect can be achieved if you have a menu with a toolbar on both the frame and the sheet. They can be assigned in any manner.
- Enabling and disabling a menu item or menu bar is less overhead to the system than Hiding/Showing. PowerBuilder destroys the current menu and recreates the original toolbar excluding the hidden items or menu bar items in case of Hiding/Showing. So whenever possible, it is better to use Enable/Disable options.
- This method of altering the states of controls at run-time is dealt in depth in PowerScript session.
Menu item names are unique throughout a menu and if you use the same text for different menu options you get an error message till you supply a different menu name.