Tkinter calling function in class through class variable

Question

I am using Tkinter and trying to call a function within a class, but not getting it to work properly.

class Access_all_elements:

        def refSelect_load_file(self): 

            self.reffname = askopenfilename(filetypes=(("XML files", "*.xml"),
                                                       ("All files", "*.*") ))
            if self.reffname:
                fileOpen = open(self.reffname)

        refSelect = Button(topFrame, text="Open Reference File", 
                    command=lambda:refSelect_load_file(self), bg = "yellow")
        refSelect.grid(row =1, column=1)

Error:

On executing above command, on pressing the button I get following error:

NameError: global name 'refSelect_load_file' is not defined

What I tried:

I tried calling a function using tkinter's generic approach which is not working for me.

refSelect = Button(topFrame, text="Open Reference File", 
                        command=refSelect_load_file, bg = "yellow")
refSelect.grid(row =1, column=1)

This throws me error:

TypeError: refSelect_load_file() takes exactly 1 argument (0 given)

Can you guys suggest me something here?

It seems unusual to me to create widgets in the class scope, rather than inside a method in the class, such as __init__. If you were in a method, you could do command=self.refSelect_load_file. — Kevin
– Kevin, Commented Jul 31, 2015 at 15:38
@Digvijayad Hey i tried it, but button got disappeared. after putting entire code in _init_ — Radheya
– Radheya, Commented Jul 31, 2015 at 15:49
Your code shows refSelect_load_file (lowercase leading "r") but the error message shows RefSelect_load_file (uppercase leading "r") — Bryan Oakley
– Bryan Oakley, Commented Jul 31, 2015 at 15:59
@BryanOakley Thanks for pointing. In my code the naming of classes is not aligned properly. I was suggested in last post to use proper name structure for classes and function. so the error you see is from names I used in my code. Sorry for that. I edited my post though Edit: it was you i see now that suggested in last post :) thanks for that. — Radheya
– Radheya, Commented Jul 31, 2015 at 16:07

Digvijayad · Accepted Answer · 2015-07-31 17:16:58Z

1

Your problem will be solved when you call the function using self.

refSelect = Button(topFrame, text="Open Reference File", 
                    command=self.refSelect_load_file, bg = "yellow")

Edit
Try this.

class Access_all_elements():
    def __init__(self):
        refSelect = Button(topFrame, text="Open Reference File", 
                command=lambda:self.refSelect_load_file, bg = "yellow")
        refSelect.grid(row =1, column=1)


    def refSelect_load_file(self): 

        self.reffname = askopenfilename(filetypes=(("XML files", "*.xml"),
                                                   ("All files", "*.*") ))
        if self.reffname:
            fileOpen = open(self.reffname)

Final Edit

from tkinter import *
from tkinter import filedialog


class Access_all_elements():

    def __init__(self):
        refSelect = Button(root, text="Open Reference File",command=self.refSelect_load_file, bg = "yellow")
        refSelect.grid(row =1, column=1)

    def refSelect_load_file(self): 
        self.reffname = filedialog.askopenfilename(filetypes=(("XML files", "*.xml"), ("All files", "*.*") ))
        if self.reffname:
            fileOpen = open(self.reffname)

root = Tk()
Access_all_elements()
root.mainloop()

edited Jul 31, 2015 at 17:16

answered Jul 31, 2015 at 15:39

Digvijayad

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7 Comments

Kevin Over a year ago

But self isn't a valid reference unless you're inside a method that has a self parameter. He's creating the button directly inside the class.

Radheya Over a year ago

@digvijayad it throws error 'self' is not defined

Radheya Over a year ago

@Digvijayad my button disappeared now. I did same.

Digvijayad Over a year ago

I forgot to put the self. in the edit... try it now. If there is error let me know the error.

Radheya Over a year ago

It shows no error. but button from GUI is gone. It disappeared.

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