tab-control

Class

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Allegro CL version 6.2
Unrevised from 6.1

tab-control

Class

The class of tab-control controls.

Control

An instance of the tab-control class. This control allows you to create a set of pages of controls and group them in related sub-groups on each tab. The Options dialog is an example of a tab-control.

Tab-controls allow overlap on their borders even when the allow overlap option is turned off. Objects overlapping a tab may or may not appear in the range and tab-info(s) for the tabs they overlap, so use this feature with care.

In Windows, the tab-order of the controls on a parent window is always the same as the front-to-back occlusion order of the controls. This means that a tab-control must be positioned in the tab order after all of the widgets that are on it, or else it will cover those widgets. This is handled automatically when designing a form window interactively, but it must be handled by the application when creating a dialog programmatically. See tab-position.

Adding a tab-control to your form

Click the tab-control tool on of the Component toolbar. Move the mouse cursor to the part of the form where you want to place the control, and click again. The control will appear with colored resizing handles.

Resizing and moving the control

Controls can only be resized and moved on forms during the design stage; the size and location of everything is fixed on a running form.

Resize the control by clicking the mouse cursor and dragging one of the handles to the new size-point. Release the mouse key when you are satisfied with the new size.

Resizing the tab-control won't mean proportional changes in the size of the characters of the labels of the tabs. Change the font property if you want to change the size of the actual characters displayed.

Move the control by clicking anywhere on it except a resizing handle and dragging it to a new location on the form. Release the mouse key when you are ready to place the control.

Moving a tab-control means dragging all of the contained objects along with it.

Adding controls to the tab-control tabs

When designing a dialog using a form, drag controls onto the individual tabs and position them. After you have added controls to each tab, you will be able to see their names in the expanded portions of the Inspector. To see the names of the controls placed on each tab in the Inspector:

Click on the tab-control to give it focus in the Inspector
Double-click on the range, making sure to click on the name of the range property (the left column) rather than the value (the right column). You will see a display of tab-info entries, one per line. There will be one tab-info for each tab in your tab-control. They will be numbered from 0 to n for (n+1) tabs.
Double-click on the value (the right hand column) for one of the tab-infos. A dialog will appear displaying the contents of the tab-info. All of the controls on that tab will appear in the value expression displayed by the dialog.
Click the OK button when you are done inspecting the expression to close the dialog.

You can also inspect the tab-infos programmatically by searching your code for calls to make-instance with tab-info for the particular tab-control you are working on.

Adding more tabs to the tab-control

Click on the tab-control to give it focus in the Inspector.
Click on the extended editor button (the one with 3 dots) for the value of the range of the tab-control.
The Edit Expression dialog will appear. You can either copy a make-info from one of the existing tabs in the dialog and paste it in another location and modify it, or just begin typing your own make-infos directly into the window.
Click the OK button when you are satisfied with your new expression. The new tab-control will appear on your form with the changes you coded in the Edit Expression dialog.