Articles for tag: combobox

To get value selected in Combobox and use it to update value in Label you can use bind() with (virtual) event '<<ComboboxSelected>>'. It can be used to assing function which will be executed you select value in Combobox - and this function may update value in Label

import tkinter as tk
import tkinter.ttk as ttk

# --- functions ---

def on_select(event):
    #print('[DEBUG] event:', event)
    #print('[DEBUG] event.widget:', event.widget)
    #print('[DEBUG] event.widget.get():', event.widget.get())
    #print('---')

    selected = event.widget.get()

    label['text'] = selected

# --- main ---

root = tk.Tk()

combo = ttk.Combobox(root, values=['A', 'B', 'C'])
combo.pack()

combo.bind('<<ComboboxSelected>>', on_select)

label = tk.Label(root) # can be without any text or ie. with `?`
label.pack()

root.mainloop()

Firts you create Combobox

combo = ttk.Combobox(root, values=['A', 'B', 'C'])
combo.pack()

Next you use bind() to assign function's name - ie. on_select - (without () and arguments) to event '<<ComboboxSelected>>' in widget Combobox

combo.bind('<<ComboboxSelected>>', on_select)

And finally create function on_select which gets one argument - ie. event - with information about event. In event you may have different information - for example event.widget gives access to widget Combobox which was used. This way you could assing the same function to two different Combobox and get access to correct widget.

def on_select(event):
    #print('[DEBUG] event:', event)
    #print('[DEBUG] event.widget:', event.widget)
    #print('[DEBUG] event.widget.get():', event.widget.get())
    #print('---')

    selected = event.widget.get()

    label['text'] = selected

And here more complex example which uses Combobox to update values in Label, Button, Entry, Listbox, Text and even in another Combobox

import tkinter as tk
import tkinter.ttk as ttk

# --- functions ---

def on_select(event):
    print('[DEBUG] event:', event)
    print('[DEBUG] event.widget:', event.widget)
    print('[DEBUG] event.widget.get():', event.widget.get())
    print('---')

    selected = event.widget.get()

    label['text'] = selected

    button['text'] = selected

    entry.delete('0', 'end')  # remove previous content
    entry.insert('end', selected)

    combobox2_values = {
        'A': ['A1', 'A2', 'A3'],
        'B': ['B1', 'B2', 'B3'],
        'C': ['C1', 'C2', 'C3'],
    }

    combobox2['values'] = combobox2_values[selected]

    listbox.delete(0, 'end')  # remove previous content
    for item in combobox2_values[selected]:
        listbox.insert('end', item)

    values = combobox2_values[selected]
    values_str = ', '.join(values)

    #text.delete('1.0', 'end')  # remove previous content
    text.insert('end', selected + ': ' + values_str + '\n')

# --- main ---

root = tk.Tk()

combobox = ttk.Combobox(root, values=['A', 'B', 'C'])
combobox.pack()

combobox.bind('<<ComboboxSelected>>', on_select)

# --- other widgets ---

label = tk.Label(root, text='?')
label.pack()

button = tk.Button(root, text='?')
button.pack()

entry = tk.Entry(root)
entry.pack()
#entry.insert(0, '?')
#entry.insert('end', '?')

combobox2 = ttk.Combobox(root)
combobox2.pack()

listbox = tk.Listbox(root)
listbox.pack()

text = tk.Text(root, width=30, height=10)
text.pack()
#text.insert('1.0', '?\n')
#text.insert('end', '?\n')

# --- 

root.mainloop()

[tkinter example combobox update other widgets]

Notes:

Different widgets may use different events and most of them use single < > in its name.
Function assigned with bind() is always executed with information about event - so it has to get this information - using argument ie. event.
<<ComboboxSelected>> event needs double << >>. In some documentations event with double << >> is called virtual event.
Function's name without () (and without arguments) which is assigned as argument in other function (which will execute it later) often is called "callback". This name is used not only in tkinter and Python but also in other modules and in other languages.
In tkinter callback is used in bind(event, callback), after(milisekundy, callback), tk.Button(..., command=callback) and in few other widgets

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# prywatne notatki - Python, Linux, Machine Learning, etc.

Tkinter: How to update widgets using value selected in Combobox?

Tkinter: Jak zmienić zawartość jakiegoś widgeta używając wartości wybranej w Combobox?