How Can You Make 3 (or 4) Nested Binded Comboxes Uting Tkinter In Python?

I am trying to make a GUI that has binding dropdowns that rely off the previous dropdown. The format that I am trying to achieve is as follows: Select a {level 1} Select a {level

Solution 1:

Here is a solution which you can improve further by add zip code too.

import tkinter as tk
from tkinter import ttk

cars = {"Bugatti":["Veyron","Golf"] ,"BMW":["330M"]}
    

defchange_dropdown(*args):

    print("Chosen brand " + tkvar.get())

    for x, y in cars.items():
        if tkvar.get() == x:
            tkvar2.set(y[0])
            popupMenu2.configure(values=y)
        
     
root = tk.Tk()
canvas = tk.Canvas(root, height=500, width= 500, bg="white")
canvas.pack()

tkvar = tk.StringVar(root)

tkvar2 = tk.StringVar(root)

tkvar3 = tk.StringVar(root)

popupMenu1 = ttk.Combobox(canvas, textvariable=tkvar, values=list(cars.keys()))
popupMenu1.pack()
popupMenu1.bind('<<comboboxselected>>', change_dropdown)

popupMenu2 = ttk.Combobox(canvas, textvariable=tkvar2, values=[])
popupMenu2.pack()
popupMenu1.bind('<<comboboxselected>>', change_dropdown)

popupMenu3 = ttk.Combobox(canvas, textvariable=tkvar3, values=[])
popupMenu3.pack()

root.mainloop()

Update:

here is the fully functioning code:

import tkinter as tk
from tkinter import ttk

cars = {"Bugatti":["Veyron","Golf"] ,"BMW":["330M"]}

_zip = [["TEST1"],["TEST2"],["TEST3"]]

lst = [x for y inlist(cars.values()) for x in y]


defchange_dropdown(*args):

    print("Chosen brand " + tkvar.get())

    if args[0] == 'PY_VAR0':
        for x, y in cars.items():
            if tkvar.get() == x:
                tkvar2.set(y[0])
                popupMenu2.configure(values=y)
        
    if args[0] == 'PY_VAR1':
        for x, y inzip(lst, _zip):
            if tkvar2.get() == x:            
                tkvar3.set(y[0])
                popupMenu3.configure(values=y)
        
    return
    
root = tk.Tk()
canvas = tk.Canvas(root, height=500, width= 500, bg="white")
canvas.pack()

tkvar = tk.StringVar(root)
tkvar.trace('w', change_dropdown)

tkvar2 = tk.StringVar(root)
tkvar2.trace('w', change_dropdown)

tkvar3 = tk.StringVar(root)

popupMenu1 = ttk.Combobox(canvas, textvariable=tkvar, values=list(cars.keys()))
popupMenu1.pack()

popupMenu2 = ttk.Combobox(canvas, textvariable=tkvar2, values=[])
popupMenu2.pack()

popupMenu3 = ttk.Combobox(canvas, textvariable=tkvar3, values=[])
popupMenu3.pack()

root.mainloop()