[Gambas-user] [Gambas-devel] Creating a Control

[Tobias Boege]

On Sun, 07 Sep 2014, John Leake wrote:
> Hi All,
> I am struggling to understand how to create  a new control. 
> 
> Please forgive me, I have read the help on this but I am none the wiser.
> 
> As a test I just want to create a control that behaves like a
> ToggleButton but changes colour each time it is clicked.
> 
> Could anyone help me get started ?
> 

Hui, I don't know how simple you think this is but depending on from where
you want to start, it can require quite some code (involving drawing every
part of your control if you want to write it from scratch). Of course, you
can, on the other side, start with a ToggleButton and add just the colour
plays to it which would require significantly less code. It depends on how
much control you need to have.

There are different approaches (hard ~ more control):
 - inherit ToggleButton [0] (easy),
 - inherit UserControl [1] (harder, chosen often in Gambas sources),
 - create a Form and put your things together [2] (less applicable here but
   useful to remember when you want to create compound controls) (also
   easy).

You may also want to integrate the control into the IDE's Form editor [3].

I tried to put example classes together for the above approaches but you are
way better off subscribing to the gambas-user mailing list (you are still on
gambas-devel here which is for discussion about contributions to Gambas, not
questions about programming in it). Some people there have done this sort of
thing way more often than me. See the SF info page [4].

Regards,
Tobi

General advice: if you have a slight idea already of what to search for, it
is a very good idea to look at the Gambas source code. Lots of things you
use as a Gambas programmer are implemented in Gambas itself.

[0] http://sourceforge.net/p/gambas/code/HEAD/tree/gambas/trunk/comp/src/gb.form/.src/MessageLabel.class
    or have a look at
    http://sourceforge.net/p/gambas/code/HEAD/tree/gambas/trunk/comp/src/gb.form/.src/TagBox/TagComboBox.class
    for an example of a very lazy coder :-)

[1] http://sourceforge.net/p/gambas/code/HEAD/tree/gambas/trunk/comp/src/gb.form/.src/Spinner.class
    This is actually a pretty good example!

[2] http://sourceforge.net/p/gambas/code/HEAD/tree/gambas/trunk/comp/src/gb.form/.src/FInputBox.class
    Plus the other *InputBox.{form,class} files in that directory.

[3] http://gambaswiki.org/wiki/dev/gambas

[4] https://lists.sourceforge.net/lists/listinfo/gambas-user

-- 
"There's an old saying: Don't change anything... ever!" -- Mr. Monk