The primary method for combining a number of widgets in a composite
widget is a WContainerWidget. This widget corresponds to an
HTML <span> or <div> element (depending on
whether it is inline or not). It can contain any number of children, and
these children may be added or removed dynamically.
Alternatives to consider are a WTemplate, which puts widgets
inside an HTML fragment using placeholder substitution, or a WTable for organizing children
in a table (without using a layout manager).
The container takes ownership of its children: when the parent
is deleted, the children will be deleted as well. This does not
stop you from deleting a child widget, as this also automatically
removes it from the parent.
As a fundamental building block of Wt, a container widget itself
usually does not have any visual aspect (although it can very
well be styled to give it for example margin and borders). The
widgets that are contained can be positioned using Cascading StyleSheets (CSS) or a Layout Manager. CSS, which
to most C++ developers will be a new technology, is worthwile
learning as it will allow you to push many layout and style
aspects of your application into a declarative text file. It
over layout managers. The latter are however the superior (and
only) choice in case vertical fitting or stretching of children
to the height of the container is needed.
There are several specialized container classes that have
additional markup or behaviour: