Python tkinter data transfer from Child to parent window on button click

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Tkinter
We will pass user entered data in one Entry area of child window. On click of button the user entered data will be passed to parent window and displayed as one existing string variable.
Pass data from child to parent windows

You can read basics of Parent and Child window here
We are using one string variable in parent window and assigned a string to it. In child window on click of a button the text entered at Entry box will transfer to parent window.

import tkinter as tk
from tkinter import * 
my_w = tk.Tk()
my_w.geometry("200x200")  # Size of the window 
my_w.title("www.plus2net.com")  # Adding a title

# create one lebel 
my_str = tk.StringVar()
l1 = tk.Label(my_w,  textvariable=my_str )
l1.grid(row=1,column=2) 
my_str.set("Hi I am main window")
# add one button 
b1 = tk.Button(my_w, text='Clik me to open new window',
               command=lambda:my_open())
b1.grid(row=2,column=2) 

def my_open():
    my_w_child=Toplevel(my_w) # Child window 
    my_w_child.geometry("250x200")  # Size of the window 
    my_w_child.title("www.plus2net.com")

    l1 = tk.Label(my_w_child,  text='Your Name', width=10 ) 
    l1.grid(row=1,column=1) 

    e1 = tk.Entry(my_w_child, width=20,bg='yellow') 
    e1.grid(row=1,column=2)
    b2 = tk.Button(my_w_child, text='Submit',
               command=lambda:my_str.set(e1.get()))
    b2.grid(row=2,column=2) 
    b3 = tk.Button(my_w_child, text=' Close Child',
                   command=my_w_child.destroy)
    b3.grid(row=3,column=2)
    
my_w.mainloop()

View & Download tkinter-toplevel-data ipynb file (.html format)

Python Tkinter Dictionary Python- Tutorials

Child to Parent data transfer