(python) Disable the button in Tkinter when passwords do not match-CodePudding

How to disable the button in tkinter window when two passwords does not match?

My work:

from tkinter import *
from functools import partial

root = Tk()
root.geometry('280x100')
root.title('Tkinter Password')

def validation_pw(ep,cp):
    if ep.get() == cp.get():
        Label(root, text = "Confirmed").grid(column=0, row=5)
    else:
        Label(root, text = "Not matched").grid(column=0, row=5)
#         check_button['state'] = DISABLED    <============================
    
ep = StringVar()
cp = StringVar()

Label1 = Label(root, text = "Enter Password").grid(column=0, row=0)
pwEnty = Entry(root, textvariable = ep, show = '*').grid(column=1, row=0) 

# Confirmed password label
Label2 = Label(root, text = "Confirm Password").grid(column=0, row=1)
pwconfEnty = Entry(root, textvariable = cp, show = '*').grid(column=1, row=1)

validation_pw = partial(validation_pw, ep,cp)

check_button = Button(root, text = "check", command = validation_pw).grid(column=0, row=4)

root.mainloop()

It shows if two passwords are not matched.

Now, I want to disable the check button if two passwords are not matched. I want the user cannot try the passwords anymore if failure.
So in the function validation_pw, I add check_button['state'] = DISABLED.
However, an error pops out

TypeError: 'NoneType' object does not support item assignment

How to fix this issue? Thanks!

CodePudding user response：

You get the error of NoneType because at one point it was assigned nothing. This is because you used .grid on the same line as the button. Fixed code:

from tkinter import *
from functools import partial

root = Tk()
root.geometry('280x100')
root.title('Tkinter Password')

def validation_pw(ep,cp):
    if ep.get() == cp.get():
        Label(root, text = "Confirmed").grid(column=0, row=5)
    else:
        Label(root, text = "Not matched").grid(column=0, row=5)
        check_button['state'] = DISABLED  
    
ep = StringVar()
cp = StringVar()

Label1 = Label(root, text = "Enter Password").grid(column=0, row=0)
pwEnty = Entry(root, textvariable = ep, show = '*').grid(column=1, row=0) 

# Confirmed password label
Label2 = Label(root, text = "Confirm Password").grid(column=0, row=1)
pwconfEnty = Entry(root, textvariable = cp, show = '*').grid(column=1, row=1)

validation_pw = partial(validation_pw, ep,cp)

check_button = Button(root, text = "check", command = validation_pw)
check_button.grid(column=0, row=4)

root.mainloop()

CodePudding user response：

Your checkbutton is actually None, because it's the result of the grid function.

To fix it, first declare the button, next grid it.

Before:

check_button = Button(
    root, text = "check", 
    command = validation_pw).grid(column=0, row=4) # Result of Button.grid function
print(check_button) # None

After:

check_button = Button(root, text = "check", command = validation_pw)
check_button.grid(column=0, row=4)
print(check_button) # Button object ...