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capture the event

SOlUTion

You were to study the three tkinter properties presented below and see
if you could match up the properties to the correct description:

WM_TAKE_FOCUS A message sent to your main window
when the operating system is shutting
down

WM_SAVE_YOURSELF A message sent to your main window
when the close-box has been clicked
WM_DELETE_WINDOW A message sent to your main window
when the window has been selected
after a mouse click

You were to identify which of these protocol messages you think you
need to capture:
WM_DELETE_WINDOW

OK... here comes a click
on the close box. What‛s my
Click! protocol? Ah, yes... it hasn‛t
been captured, so I‛ll just
execute the default behavior
? and close that sucker!

Controlling the Window Manager

To capture the event before it gets to tkinter, call your app’s You'll have to create the
protocol() method and identify the function that should be “shutdown” function.
called instead of executing the default behavior:

Be sure to call app.protocol("WM_DELETE_WINDOW", shutdown) Associate the event-
“protocol()" BEFORE handling function
“mainloop()". with the property.

322 Chapter 9