Tkinter ttk Treeview binding responds to past events!

[John O'Hagan]

On Tue, 2023-09-12 at 20:51 +0200, Mirko via Python-list wrote:
> 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
> 
> [. . .]

Thanks (also to others who have explained), now I get it!


> 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()
> 


I like this solution better - it's much more obvious to me what it's
doing.

Regards

John