calling functions from a different window

wxPython Users
1

Mark:

Thanks for the help, excellent teaching. I’ve got things working based on your examples; doesn’t seem too hard now but I was missing a few of the details.

Mike

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On Dec 6, 2007 3:33 PM, Mark Erbaugh < mark@microenh.com> wrote:

On Thu, 2007-12-06 at 13:12 -0600, Michael Barron wrote:

As someone who is new to programming I am still struggling with doing
things between windows. The namespace issues give me a lot of
trouble. Robin Dunn had a good response on 30 Nov about transferring

data between a dialog and a frame. I was wondering about calling
methods from a different class. I have a dialog that I want to do
several things on a notebook page but I can’t seem to find the right

way to do it.

So far I’ve tried calling the method using the instance names for the
notebook page’s class. This ends up looking like
“app.frame.nb.page3.UpdatePage().” I get an error saying ‘app’ is

unknown. I’ve also tried called .GetTopLevelParent() but this
apparently is the dialog itself; no parent I guess. I read in the
book about finding windows by their id, name or label but I’m not sure

how to do this. I’ve messed around on PyCrust with passing instance
names to other classes in order to call their methods but doing this
in a GUI environment is difficult for me.

This subject seems like a good one for a tutorial. Is there one out

there I am missing?

Thanks for the help.

Mike,

The first thing you need to get your head around is the concept of
classes and instances. When you define a Frame, you are usually

sub-classing the existing wx.Frame class. This creates a new class.
However, when your code runs it actually creates an instance of this
class. Think of the class as the template or pattern for an object, an

instance is the actual object created from that template. It is common
to create more than one instance of the same class.

In Python (and wxPython) an instance is created when you “call” the
class name. If your frame class is CompanyFrame, you probably have code

like:

frameCompany = CompanyFrame(None, -1, ‘’)
frameCompany.Show()

Your parameters in the parenthesis may be slightly different. The first
statement creates an instance of the CompanyFrame class and stores a

reference to it in the frameCompany variable. The second line then
calls the Show method of this instance.

In some cases, you may combine the two and have a statement like:

CompanyFrame(None, -1, ‘’).Show()

This creates the instance and calls the Show method. The difference is
that it does not create a reference that you can work with. I suspect
that this is your problem.

What I would recommend is that you create a reference as in the first

example. Then pass that reference to the dialog class instance. For
example, Assume your dialog class is DialogClass

dialog = DialogClass(…)
dialog.company_frame = frameCompany

Then in the dialog you can access the items in the CompanyFrame instance

self.company_frame.nb.page3.UpdatePage().

As an aside, I wonder if nb.page3 is the correct way to access that
widget. While visually, page3 is on the notebook and the notebook is on
the form, the way I typically design a screen, the page3 widget is a

data member of the frame, not a data member of the notebook widget, so
the reference would be company_frame.page3.UpdatePage(), leaving out the
nb.

I hope this helps.

Mark

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