Tkinter ttk Treeview binding responds to past events!

[Mirko]

Am 12.09.23 um 07:43 schrieb John O'Hagan via Python-list:

> My issue is solved, but I'm still curious about what is happening here.

MRAB already said it: When you enter the callback function, Tk's 
mainloop waits for it to return. So what's happening is:

1. Tk's mainloop pauses
2. temp_unbind() is called
3. TreeviewSelect is unbound
4. events are queued
5. TreeviewSelect is bound again
6. temp_unbind() returns
7. Tk's mainloop continues with the state:
	- TreeviewSelect is bound
	- events are queued

Am 11.09.23 um 23:58 schrieb Rob Cliffe:

> Indeed.  And you don't need to specify a delay of 100 milliseconds. 0 will work (I'm guessing that's because queued actions are performed in the order that they were queued).

Ah, nice, didn't know that!

> I have also found that after() is a cure for some ills, though I 
> avoid using it more than I have to because it feels ... a bit 
> fragile, perhaps.
Yeah. Though for me it was the delay which made it seem fragile. 
With a 0 delay, this looks much more reliable.


FWIW, here's a version without after(), solving this purely on the 
python side, not by temporarily unbinding the event, but by 
selectively doing nothing in the callback function.

from tkinter import *
from tkinter.ttk import *

class Test:
     def __init__(self):
         self.inhibit = False
         root=Tk()
         self.tree = Treeview(root)
         self.tree.pack()
         self.iid = self.tree.insert('', 0, text='test')
         Button(root, command=self.temp_inhibit).pack()
         mainloop()

     def callback(self, *e):
         if not self.inhibit:
             print('called')

     def temp_inhibit(self):
         self.inhibit = True
         self.tree.selection_set(self.iid)
         self.tree.selection_remove(self.iid)
         self.tree.selection_set(self.iid)
         self.inhibit = False
         self.callback()

c=Test()


HTH and regards