In part 1 of this tutorial, we covered the basics of Win32::GUI programming, using a simple label control to display information. But real-world applications don't just display information as labels. We need to be able to obtain information from the user, respond to mouse clicks, etc etc.
Some of the basic Windows controls supported by Win32::GUI include
We have already covered nearly all of the programming techniques for using these controls in our discussion of the label control in part 1. The following section summarises the basic controls available, and any important issues regarding their use. Armed with this and the main Win32::GUI documentation, it should be possible to develop reasonably complex applications.
For this part of the tutorial, we will use a very basic "framework" application, to which we can add functionality. We won't worry about issues like positioning, layout, resizing, etc, as these will only distract from the main point, which is the control handling.
So, our basic application is
use Win32::GUI();
$main = Win32::GUI::Window->new(-name => 'Main', -text => 'Perl',
-width => 200, -height => 200);
$main->Show();
Win32::GUI::Dialog();
sub Main_Terminate {
-1;
}
Now, the basic approach to adding any control to a window is the same. We saw
it before, when we added a label. We simply use the window's AddXXX() method,
where XXX is the control type we want to add. So, we have, AddButton(),
AddTextfield(), AddCheckbox(), AddCombobox(), AddListbox(), AddRadioButton(),
etc.
All of these methods work the same way, in that they take a series of options,
which define the appearance and behaviour of the control. Many of the options
are common to all Win32::GUI controls (such as -width and -height) but a
few are control-specific.
The controls themselves support events, much like the main window with its
Terminate event. Events are control-specific, but tend to be fairly general
(many controls have a Click event, which occurs when the user clicks the
mouse on the control, for example).
None. We saw labels in some detail in the last part of this tutorial. Most of what we learnt applies equally to all other controls.
None. To make a button do something, add a handler for the Click event.
To get or set the "checked" state, use the Checked() method. There are three
states - unchecked (0), checked (1) and indeterminate or grayed (2). Use the
Click event to respond to changes in state.
To get or set the contents of the text field, use the -text option. The
-multiline option allows entry of more than one line of text (but beware -
the -text option contains a CRLF sequence ("\r\n") at the end of each line,
not just LF ("\n") as is normal for Perl. See the documentation for the
-prompt option to automatically add a label to a text field.
A display-only control. Set the parameters with the SetRange() and SetStep()
methods, and update the display using the SetPos() or StepIt() methods.
By default, there are no items in the list. Fill the list box using the
AddString() method. Get the selected item using the SelectedItem() method.
Multiple-selection listboxes are created using the -multisel option -- in
that case, use the SelectedItems() method to get a list of all the selected
items.
Similar to single-selection list boxes (although they display differently).
This is the little double-arrow control you often see attached to numeric text fields in dialog boxes. Clicking the up arrow increases the value of the text field, whereas clicking the down arrow decreases it.
The only significant complication with using an UpDown control is the need to
associate it with a text box. This is done using the Buddy() method, as
$updown->Buddy($text)
Methods exist to set the range of values for the control, and to explicitly
set the value of the control. The control supports a Scroll event, which is
fired when the control value changes (but not when the associated text box
changes!) The UpDown control's size is ignored, as it is attached to its buddy
when it is created.
This covers the basic controls available in Win32::GUI. In part 3, we will cover some of the subtleties of dialog boxes and main windows, and then in part 4, we will be ready to cover some of the more complex user interface options.
Documentation for Win32::GUI v1.06 created 13 Feb 2008
This document is autogenerated by the build process. Edits made here will be lost. Edit docs/GUI/Tutorial/Part2.pod instead.
Homepage: http://perl-win32-gui.sourceforge.net/.
For further support join the users mailing list(perl-win32-gui-users@lists.sourceforge.net) from the website
at http://lists.sourceforge.net/lists/listinfo/perl-win32-gui-users. There is a searchable list archive at http://sourceforge.net/mail/.
Copyright (c) 1997..2008 Aldo Calpini. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
