Which events can be bound to a Tkinter Frame?

Question

I am making a small application with Tkinter. I would like to clean few things in a function called when my window is closed. I am trying to bind the close event of my window with that function. I don't know if it is possible and what is the corresponding sequence.

The Python documentation says: See the bind man page and page 201 of John Ousterhout’s book for details.

Unfortunately, I don't have these resources in my hands. Does anybody know the list of events that can be bound?

An alternative solution would be to clean everything in the __del__ of my Frame class. For an unknown reason it seems that it is never called. Does anybody knows what can be the cause? Some circular dependencies?

As soon as, I add a control (uncomment in the code below), the __del__ is not called anymore. Any solution for that problem?

from tkinter import *

class MyDialog(Frame):
    def __init__(self):
        print("hello")
        self.root = Tk()
        self.root.title("Test")

        Frame.__init__(self, self.root)
        self.list = Listbox(self, selectmode=BROWSE)
        self.list.pack(fill=BOTH, expand=1)
        self.pack(fill=BOTH, expand=1)


    def __del__(self):
        print("bye-bye")

dialog = MyDialog()
dialog.root.mainloop()

Answer 1

I believe this is the bind man page you may have been looking for; I believe the event you're trying to bind is Destroy. __del__ is not to be relied on (just too hard to know when a circular reference loop, e.g. parent to child widget and back, will stop it from triggering!), using event binding is definitely preferable.

Answer 2

A more-or-less definitive resource for events is the bind man page for Tk. I'm not exactly clear what you're wanting to do, but binding on "<Destroy>" is probably the event you are looking for. Whether it does what you really need, I don't know.

 ...
 self.bind("<Destroy>", self.callback)
 ...
 def callback(self, event):
     print("callback called")