Re: Tkinter button not working as expected

vagrantbrad@xxxxxxxxx wrote:
I've created a short test program that uses tkFileDialog.askdirectory
to help the user input a path into a tk entry widget. The problem I'm
having is that when I run the code as listed below, the getPath
function is called when the program initially runs, not when the button
is pressed.

from Tkinter import *
import tkFileDialog

class App:

def __init__(self, master):

frame = Frame(master)
frame.pack()

t = StringVar()
self.entry = Entry(frame, textvariable=t)
self.entry.pack(side=LEFT)

self.button = Button(frame, text="Select", fg="red")
self.button["command"] = self.getPath(t)
self.button.pack(side=LEFT)

def getPath(self, t):
dirPath = tkFileDialog.askdirectory(initialdir="c:\\")
print dirPath
t.set(dirPath)

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


The problem arises when I try to pass the t variable in the "command"
option of the button widget. If I set the command to
"command=self.getpath" rather than "command=self.getpath(t)", then I
don't get this issue. But I would like to be able to pass a variable
to the the function through the command option. I'm a Tk newbie ....
what am I doing wrong?


Well, in python 2.5, you might consider functools.partial.

Other options, including lambda, will be suggested and are the traditional way to do this sort of thing.

Here is the revised code:

import functools
from Tkinter import *
import tkFileDialog

class App:

def __init__(self, master):

frame = Frame(master)
frame.pack()

t = StringVar()
self.entry = Entry(frame, textvariable=t)
self.entry.pack(side=LEFT)

self.button = Button(frame, text="Select", fg="red")

# note change here
self.button["command"] = functools.partial(self.getPath, t)
self.button.pack(side=LEFT)

def getPath(self, t):
dirPath = tkFileDialog.askdirectory(initialdir="c:\\")
print dirPath
t.set(dirPath)

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




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James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/
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