Tkinter: how to pass variable from one class (window) to another class (window)

In tkinter with python, how do I pass the value of a variable from one class (window) to another class (window), when that class reuses the same frame (it's not a toplevel window).

For example I have a login window, which I would like to pass the username and account privilege type (Admin, Operator...) to the main window. How to do this?

See the example files:

main.py

#!/usr/bin/env python3

from tkinter import *
from frm_login import Wlogin

class Mainframe(Tk):
    def __init__(self):
        Tk.__init__(self)
        self.frame = Wlogin(self)
        self.frame.pack()

    def change(self, frame):
        self.frame.pack_forget() # delete currrent frame
        self.frame = frame(self)
        self.frame.pack() # make new frame


if __name__== '__main__':
    app = Mainframe()
    app.mainloop()

frm_login.py

from tkinter import *
from frm_default import Wmain

class Func(Frame):
    def go_to_main(self, event=None):
        self.myvar = self.entry_var.get() #pass the value of this variable to the class: Wmain
        self.master.change(Wmain)


class Wlogin(Func):
    def __init__(self, master=None, **kwargs):
        Frame.__init__(self, master, **kwargs)

        master.title('First Window')
        master.geometry('300x200')

        self.myvar = StringVar()

        self.entry_var = Entry(self, textvariable=self.myvar)
        self.entry_var.pack()
        self.entry_var.focus()

        self.btn = Button(self, text='Go', command=self.go_to_main)
        self.btn.pack()

frm_default.py

from tkinter import *

class Wmain(Frame):
    def __init__(self, master=None, **kwargs):
        Frame.__init__(self, master, **kwargs)
        master.title('Second Window')
        master.geometry('600x400')

        self.label_var = Label(self, bg='red', fg='#ff0', text='How to show var of first window here?')
        self.label_var.pack()

CodePudding user response：

One of the way is to pass the required value via kwargs:

main.py

class Mainframe(Tk):
    def __init__(self):
        Tk.__init__(self)
        self.frame = Wlogin(self)
        self.frame.pack()

    # added **kwargs
    def change(self, frame, **kwargs):
        self.frame.pack_forget() # delete currrent frame
        self.frame = frame(self, **kwargs) ### pass **kwargs
        self.frame.pack() # make new frame

frm_login.py

class Func(Frame):
    def go_to_main(self, event=None):
        self.myvar = self.entry_var.get() #pass the value of this variable to the class: Wmain
        self.master.change(Wmain, data=self.myvar) # pass value via keyword 'data'

...

frm_default.py

class Wmain(Frame):
    def __init__(self, master=None, **kwargs):
        # get the value of keyword argument 'data'
        data = kwargs.pop('data', None)
        Frame.__init__(self, master, **kwargs)
        master.title('Second Window')
        master.geometry('600x400')

        self.label_var = Label(self, bg='red', fg='#ff0', text=data) # use 'data'
        self.label_var.pack()