Am 14.06.18 um 05:14 schrieb huey.y.ji...@gmail.com:
root = Tkinter.Tk()
button = Tkinter.Button(root, text="Find me")
button.pack()
I created a button, Python object. I recall I can check this object existing by using winfo, such as winfo.exists(button). However, I forgot which super class contains this winfo method. I printed out dir(os), dir(sys), dir(Tkinter), but did not find this winfo method. I wonder who will be kindly drop down a few lines?
This is due to a bad wrapping of the original Tcl interface of Tk. In
the original Tcl, "winfo" is not a method of anything, it is a free
function. In TkInter, all free functions that accept a widget as the
first parameter were made methods of that widget. Therefore,
"winfo_exists" is a method of "button", which is logically contorted:
you are asking an object "do you exist?".
However, since it can be explicitly destroyed, this can still be useful:
>>> import Tkinter
>>> root = Tkinter.Tk()
>>> button = Tkinter.Button(root, text="Find me")
>>> button.pack()
>>> button.winfo_exists()
1
>>> button.destroy()
>>> button.winfo_exists()
0
I am not sure that this is very helpful, though. Usually you don't
destroy a button yourself, it is done by the destructor when the button
is deleted, and therefore, winfo_exists() under normal circumstances
returns true. What are you really trying to achieve?
Christian
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