How to write a txt file from python GUI?-CodePudding

I am currently trying to make a simple GUI which asks a user his age and name. The names then get stored in a txt file but the GUI is working fine but the names are not getting stored in a txt file. I am getting this error -->

Exception in Tkinter callback Traceback (most recent call last): File "C:\Python39\lib\tkinter_init_.py", line 1892, in call return self.func(*args) File "c:\Users\Sumit\vs code python\projects\tkinter_course\tut_10.py", line 17, in getvals f.write(f"{uservalue.get()}") ValueError: I/O operation on closed file.

The code which I am trying to run is as follows -->

from tkinter import *
t = (r'C:\Users\Sumit\vs code python\projects\y.txt')
root = Tk()
root.geometry("655x333")

root.title("dance class forum")


user = Label(root, text="Name")
password = Label(root, text="Age")
user.grid() 
password.grid(row=1)
f = open(t, "a")
# Variable classes in tkinter
# BooleanVar, DoubleVar, IntVar, StringVar
def getvals():
    f.write(f"{uservalue.get()}")
    f.write('\n')
    f.write(f"{passvalue.get()}")
  

uservalue = StringVar()
passvalue = StringVar()
f.close()

userentry = Entry(root, textvariable = uservalue)
passentry = Entry(root, textvariable = passvalue)

userentry.grid(row=0, column=1)
passentry.grid(row=1, column=1)

Button(text="Submit", command=getvals).grid()

root.mainloop()

CodePudding user response：

This error tells you everything you need to know.

ValueError: I/O operation on closed file.

It tried writing to a file, but the file is closed. You are prematurely closing the file before starting the main loop.

f = open(t, "a")
f.close()

# When the button is clicked and getvals is called, the file is already closed
Button(text="Submit", command=getvals).grid()

root.mainloop()

The simplest solution is to only open the file when you need to write to it.

# No longer needed
# f = open(t, "a")
# f.close()

def getvals():
    with open(t, "a") as f:
        f.write(f"{uservalue.get()}")
        f.write('\n')
        f.write(f"{passvalue.get()}")

Using a with statement will automatically close the file after it finishes executing everything inside the with. Opening a file is a quick operation so it's not necessary to open it ahead of time.