Teach Yourself Borland C++ in 14 Days - portal

260 Day 7
Pop-up Menus (Speed Menus)
We’re not quite done with our discussion of menus. In C++Builder, you can create pop-up
menus as easily as you can create a main menu. A nice feature of C++Builder is that you can
assign a particular pop-up menu to a component via the PopupMenu property of the
component. When the cursor is placed over the component and the secondary mouse button
is clicked, that pop-up will automatically be displayed. Writing event handlers for pop-up
menus is exactly the same as writing event handlers for main menus.
A common feature of text-editing programs is that the Cut, Copy, and Paste operations are
on a speed menu. We’ll add that capability to ScratchPad. To create the pop-up, we’ll cheat
and copy part of the main menu. Here we go:
1. Choose a PopupMenu component from the Component Palette and place it on the
form.
2. Change the Name property to MemoPopup.
3. Double-click the PopupMenu icon to run the Menu Designer.
4. Click the secondary mouse button to bring up the Menu Designer speed menu.
Choose Select Menu from the speed menu. A dialog box is displayed that shows
the menus available for your application. Choose MainMenu and click OK.
5. Click on the Edit menu. Click on the Cut menu item, hold down the Shift key,
and click on the Paste menu item. Cut, Copy, and Paste are all now highlighted.
6. To copy the selected items to the Clipboard, choose Edit | Copy from the
C++Builder main menu (don’t choose Edit | Copy from the menu you are creating
in the Menu Designer) or press Ctrl+C.
7. Again, choose Select Menu from the Menu Designer speed menu. This time, choose
MemoPopup and click OK. The Menu Designer shows a blank pop-up menu.
8. Choose Edit | Paste from the main menu or type Ctrl+V on the keyboard. The
Cut, Copy, and Paste menu items are inserted into the pop-up.
Okay, just a few more things and we’ll be done. We need to change the Name property for the
new menu items:
1. For the Cut menu item, change the Name property to PopupCut.
2. Change the Name property for the Copy menu item to PopupCopy.
3. Finally, change the Name property for the Paste menu item to PopupPaste.
The final step is to write event handlers for the pop-up menu items. Hmmm…we already have
code written for the main menu’s Cut, Copy, and Paste items. It would be a shame to duplicate
that code (even if it is just a single line in each case). It would be nice if we could just use the
same event handlers that we created earlier. Can we? Sure we can! Just follow these steps: