Column Name: Advanced PM Programming
Column Title: Introducing Containers


Written by Guy Scharf. Published in the December issue of OS/2 Monthly.
(c) Copyright 1992 Software Architects, Inc.


<BIntroducing Containers>

OS/2 2.0 introduces four new controls-slider, value set,
notebook, and container.  This month we will take a first
look at containers.

First, what <Iis> a container?  You have seen containers-lots
of them. The container control is one of the key
components of the Workplace Shell.  A container displays
to the user the items, or objects, in contains in a visual
way.  Virtually everything you see on the OS/2 desktop
before starting a program or opening a settings view is a
container.

If you open the drives folder, select a drive, and open it,
you will see <I>a container showing directories on the drive,
arranged hierarchially.  This representation is called a tree
view.  Select Open from the system menu again, press the
right arrow button, and you can open Settings, Icon view,
Tree view, and Details view.  These three views are all
different ways a container can display the directories and
files on a drive.

The container control supports five views of its contents:

Icon View     Icons or bitmaps with strings beneath. 
              The Workplace Shell desktop normally
              displays objects this way.

Name View     Icons or bitmaps with text to the right.

Text View     Text strings without any pictorial
              representation.

Tree View     Icons or bitmaps with text to the right
              and with a way to display a hierarchy
              (often indicated by + and - signs).

Details View  Icons or bitmaps, text strings, numbers,
              times, and/or dates.

Container windows support <Idirect manipulation>-the user
can select items with the mouse and drag them around. 
The user can drag items and drop them onto other
containers, applications, or windows.

It is the container control that gives OS/2 2.0 and the
Workplace Shell much of its flavor.

A container may change the way in which its contents are
displayed by changing the view.  In the Workplace Shell,
different views are typically seen by opening windows with
that alternate view.  It is possible to change the view within
a single window.  Only one view can be displayed in one
container window at a time.


The remainder of this article can be found in the December issue of OS/2 Monthly.