CODEWITHSUNDEEP
pythonpython-3.xtkintercombobox
jasuramme
jasuramme

Reputation: 31

How to bind keypress event for combobox drop-out menu in tkinter Python 3.7

I want to make a feature: when my combobox in tkinter clicked and drop-down menu is opened, when you press any key (for example 's'), it selects first element in combobox, starting with 's' letter. But I cannot find out, how to bind it straight to listBox, which is created by combobox. If I bind keyPress events to combobox, it does not receive events, when drop-down menu opened.

So, I tried stuff like this: self.combobox.bind("<KeyPress>", self.keyPressed) but no success.

Can you please advice me the way how to do that? Or if it possible at all?

UPDATED: tiny code example

import tkinter as tk
from tkinter import ttk

def pressed(evt):
    print ("key pressed")

f = tk.Frame();
f.grid()
c = ttk.Combobox(f,values = ["alfa","betta","gamma"])
c.grid(column = 0, row = 0)
c.bind("<KeyRelease>",pressed)
f.mainloop()

Upvotes: 1

Views: 2877

Answers (2)

Angy
Angy

Reputation: 1

Based on your code, when a key/character is typed (like "s"), the first item starting with the letter in the combobox is selected (if it exists) and if the same key is selected, the next item is selected:

def pressed(event):
    widget = event.widget
    matching_values = [item for item in widget['values'] if item.lower().startswith(event.char.lower())]
    # Select the first matching item if available
    if matching_values:
        current_value = widget.get()
        for i, val in enumerate(matching_values):
            if current_value == val:
                break
        i = 0 if i >= len(matching_values)-1 else i+1
        widget.set(matching_values[i])  # Set the combobox to the first match

Upvotes: 0

jasuramme
jasuramme

Reputation: 31

As far as I understood, there no way to get popdown menu in Python currently. And you have to do that through TCL. The weak point is ".f.l" part of reference as it depends on internal widgets implementation. There is an example of combobox, wich will select items by first their letter when you press a keyboard button.

from tkinter import ttk
import itertools as it

class mycombobox(ttk.Combobox):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        pd = self.tk.call('ttk::combobox::PopdownWindow', self) #get popdownWindow reference 
        lb = pd + '.f.l' #get popdown listbox
        self._bind(('bind', lb),"<KeyPress>",self.popup_key_pressed,None)

    def popup_key_pressed(self,evt):
        values = self.cget("values")
        for i in it.chain(range(self.current() + 1,len(values)),range(0,self.current())):
            if evt.char.lower() == values[i][0].lower():
                self.current(i)
                self.icursor(i)
                self.tk.eval(evt.widget + ' selection clear 0 end') #clear current selection
                self.tk.eval(evt.widget + ' selection set ' + str(i)) #select new element
                self.tk.eval(evt.widget + ' see ' + str(i)) #spin combobox popdown for selected element will be visible
                return

Upvotes: 2

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