Show combobox drop down while editing text using tkinter

Question

Is it possible to make Combobox editable while dropdown is opened? I haven't found any solution. I want to make it more like Google Search but using ComboBox.

Answer 1

Question: Show Combobox PopdownWindow, while editing text

This example extends a ttk.Combobox to the following:

• Show the PopdownWindow while typing
• Open the PopdownWindow on Key-pressed '<Down>'
• Close the PopdownWindow on Key-pressed '<Up', if at the first item in the Listbox

---

Reference:

• Events and Bindings

  For each widget, you can bind Python functions and methods to events.

• ttk::combobox — text field with popdown selection list

  The ttk::combobox uses the entry and listbox widgets internally.

---

1. Inherit from ttk.Combox

   import tkinter as tk
   import tkinter.ttk as ttk
   
   
   class Combobox(ttk.Combobox):
   

2. Helper function, to map the internal Toplevel and Listbox to a tkinter object.

   WARNING: This uses Tk/Tcl internals, which could change without notice.
   This may working only with the tested Tk/Tcl version!

   def _tk(self, cls, parent):
       obj = cls(parent)
       obj.destroy()
       if cls is tk.Toplevel:
           obj._w = self.tk.call('ttk::combobox::PopdownWindow', self)
       else:
           obj._w = '{}.{}'.format(parent._w, 'f.l')
       return obj
   

3. Initalize the object, get the internal references and bind to Key-press events

   def __init__(self, parent, **kwargs):
       super().__init__(parent, **kwargs)
       self.popdown = self._tk(tk.Toplevel, parent)
       self.listbox = self._tk(tk.Listbox, self.popdown)
   
       self.bind("<KeyPress>", self.on_keypress, '+')
       self.listbox.bind("<Up>", self.on_keypress)
   

4. Key-pressed handler to show or hide the PopdownWindow and set the Keyboard focus.

   def on_keypress(self, event):
       if event.widget == self:
           state = self.popdown.state()
   
           if state == 'withdrawn' \
                   and event.keysym not in ['BackSpace', 'Up']:
               self.event_generate('<Button-1>')
               self.after(0, self.focus_set)
   
           if event.keysym == 'Down':
               self.after(0, self.listbox.focus_set)
   
       else:  # self.listbox
           curselection = self.listbox.curselection()
   
           if event.keysym == 'Up' and curselection[0] == 0:
               self.popdown.withdraw()
   
   

   Usage:

   class App(tk.Tk):
       def __init__(self):
           super().__init__()
   
           values = ('one', 'two', 'three', 'four', 'five', 'six', 'seven')
   
           self.cb = Combobox(self, value=values)
           self.cb.grid(row=0, column=0)
   
   
   if __name__ == "__main__":
       App().mainloop()
   
   

   Tested with Python: 3.5 - 'TclVersion': 8.6 'TkVersion': 8.6