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Class Reference Problems

To: gettingstarted at lists dot realsoftware dot com
Subject: Class Reference Problems
From: Scott Goelzer <srg42 at comcast dot net>
Date: Sat, 26 Feb 2005 18:41:44 -0500
Delivered-to: gettingstarted at lists dot realsoftware dot com
References: <20050222234319 dot 1D81674C4D4 at lists dot realsoftware dot com>
I'm stuck,


I have a window with a listbox and a canvas. The listbox has a custom super class with functions to manage the columns; it stores a copy of the data in a property and has functions to manage the data. The canvas has another superclass to manage its image. Specifically, the canvas superclass has a picture property which is drawn to the canvas when a refresh is needed. The canvas super class draws data from the list superclass to create its picture. When the listbox changes, the canvas changes and all is well.

UNTIL
I create another window. My understanding was that creating another window would create another instance of everything in the window. I would get another canvas and another listbox and instances of their super classes as well. These would maintain their functions independently of the other window and I would pat myself on the back for almost understanding object programming.

BUT
When I create the new window the listbox and its superclass work as expected. Data is stored and managed independently. However the canvas and its super class are still linked to the original window listbox. It truly mystifies my why one works and the other does not.

Any ideas on where I went wrong or what concept I do not understand?

I think the problem is how the canvas super class is addressing the listbox super class. The call I am using from the canvas superclass is:

datawnd.listbox1.whateverIneeded

or maybe the problem is that when I create the new window, I am not truly creating more instances of the superclasses. If so how do I do this since the first instances were created automatically when the first window came up.



Thanks
Scott



*******************************************
Scott Goelzer
Physics Teacher
Coe-Brown Northwood Academy
Northwood NH 03261
s dot goelzer at comcast dot net
*******************************************

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