The Scrollbar Widget
Instead of
automatically creating one or more Scrollbars with the
Scrolled
method, you can use the
Scrollbar
widget method and perform the
configuration yourself. It is better to create and configure your own
Scrollbars when you need to do something nonstandard, such as have
one Scrollbar scroll two Listboxes. Figure 6-6
shows a Scrollbar widget.
Figure 6-6. Scrollbar widget
Creating a Scrollbar Widget
To create
the Scrollbar, invoke the Scrollbar
method from
the parent widget. It returns a reference to the newly created
Scrollbar that you can use for configuration:
$scrollbar = $mw->Scrollbar([ options ...]
)
There are at least two other things you
need to do to get a Scrollbar working with another widget. First,
create the to-be-scrolled widget and use the Scrollbar with its
-xscrollcommand
or
-yscrollcommand
option. Then configure the
Scrollbar so that it knows to talk to that widget. Here’s an
example that creates a Listbox widget (don’t worry if you
don’t quite follow all of this now; we just want to show a
complete example before we go on to talk about all the options):
# Create the vertical Scrollbar $scrollbar = $mw->Scrollbar( ); $lb = $mw->Listbox(-yscrollcommand => ['set' => $scrollbar]); #Configure the Scrollbar to talk to the Listbox widget $scrollbar->configure(-command => ['yview' => $lb]); #Pack the Scrollbar first so that it doesn't disappear ...
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