Tk variables problem

[David Fisher]

>>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<<

On 2/2/00, 7:10:50 AM, "Sven Drescher" <Sven.Drescher at dlr.de> wrote 
regarding Tk variables problem:
> Hi!

> I cannot understand why the following little program doesn't work 
correct.
> It's surely a little problem, but in my program are more situations, 
where
> such an error is raised.
> I thought, there isn't a problem, but...

> Tanks for hints, what I did wrong.
> Sven

> e.g.:
> #!/usr/.../python
> import Tkinter

> class test:
>     def __init__(self):
>         self._bool=Tkinter.BooleanVar()
>         self._bool.set(1)
>         self.display()

>     def display(self):
>         print "Hi!"
>         print "The value is ", self._bool.get()

> a=test()
> a.hallo()

> error:
> Variable.__init__(self, master)
> self._tk = master.tk
> Attribute Error: 'None' object has no attribute 'tk'
> ...

you need to instantiate a root window, like this:

root = Tkinter.Tk()

before you make the call to Tkinter.BooleanVar().

David Fisher

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