On Wed, 24 Aug 2005 15:07:27 GMT, William Gill <[EMAIL PROTECTED]> wrote:
> Working with tkinter, I have a createWidgets() method in a class.
> Within createWidgets() I create several StringVars() and
> assign them to the textvariable option of several widgets.
> Effectively my code structure is:
>
> def createWidgets(self):
> ...
> var = StringVar()
> Entry(master,textvariable=var)
> ...
> ...
>
> Though 'var' would normally go out of scope when createWidgets
> completes, since the Entry and its reference do not go out of scope,
> only the name 'var' goes out of scope, not the StringVar object, Right?
Well, apparently not:
------------------------------------------------
from Tkinter import *
class MyStringVar(StringVar):
def __del__(self):
print "I'm dying!"
root = Tk()
def cw():
var = MyStringVar()
Entry(root, textvariable=var).pack()
cw()
root.mainloop()
------------------------------------------------
Running this script actually prints "I'm dying!", so there is obviously no
reference from the Entry widget to the variable object. The reference is
actually kept at tcl level between an entry and the *tcl* variable, which knows
nothing about the *Python* variable.
BTW, the whole purpose of StringVar's is to be kept so that the text for the
entry can be retrieved or modified by another part of the program. So what can
be the purpose of creating variables in a function or method and not keeping
them anywhere else than a local variable?
--
python -c "print ''.join([chr(154 - ord(c)) for c in
'U(17zX(%,5.zmz5(17;8(%,5.Z65\'*9--56l7+-'])"
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