help with an error in Tkinter

[Ivan Van Laningham]

Hi All--

Wayne wrote:
> 
> Hello,
> I'm reading the book(?) " An introduction to Tkinter" and in doing one

??  Who's the author?

> of the example
> on Checkbutton Widget I get an error that I don't know how to resolve.
> Here is the program
> with a slight change - I left the "Quit" button code in from an earlier
> example.
> 
> from Tkinter import *
> 
> class App:
>      def __init__(self, master):
>           self.var = IntVar()
>           c = Checkbutton(master, text = "Enable Tab", variable =
> self.var, command = self.cb
>           c.pack()
> 
>           self.button = Button(master, text = "Quit", fg = "red",
> commnad = master.quit
>           self.button.pack()
> 
>      def cb(self, event):
>           print "variable is", self.var.get()
> 
> root = Tk()
> app = App(root)
> root.mainloop()
> 
> The error I'm getting:
> 
> Exception in Tkinter callback
> Traceback (innermost last):
> File "/var/tmp/python-root/usr/lib/python1.5/lib-tk/Tkinter.py", line
> 752, in __call__
> return apply(self.func, args)
> TypeError: not enough arguments; expected 2, got 1
> 

Here's a corrected version:

from Tkinter import *

class App:
     def __init__(self, master):
          self.var = IntVar()
	  # You need to close the parens.
          c = Checkbutton(master, text = "Enable Tab", variable
=self.var, command = self.cb)
          c.pack()
	  # You need to close the parens, and spell it "command", not "commnad"
          self.button = Button(master, text = "Quit", fg = "red",
command = master.quit)
          self.button.pack()
          # And here, the "command" callback doesn't get passed the
"event" parameter.
     def cb(self, event=0):
          print "variable is", self.var.get()

root = Tk()
app = App(root)
root.mainloop()


Proofread lots.
<or,-measure-three-times-cut-once>-ly y'rs,
Ivan;-)
----------------------------------------------
Ivan Van Laningham
Callware Technologies, Inc.
ivanlan at callware.com
ivanlan at home.com
http://www.pauahtun.org
See also: 
http://www.foretec.com/python/workshops/1998-11/proceedings.html
Army Signal Corps:  Cu Chi, Class of '70
Author:  Teach Yourself Python in 24 Hours
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