[Tkinter-discuss] Checkbutton and Radiobutton in 3rd state

[Michael Lange]

Hi,

On Sat, 2 Dec 2017 21:18:14 +0000
adil gourinda <rikudou__sennin at live.com> wrote:

>    In "tkinter.Chechbutton()" and "tkinter.Radiobutton()" widgets if
> the "tristatevalue" option is set to an empty string the indicator
> appears the first time in the 3rd state in which it is gray, but if I
> check the button multiple times I can't put the indicator again in the
> 3rd state, and if I set the "tristatevalue" to other value the
> indicator doesn't appear in the 3rd state
> Thank you for your help

the third state can be accessed if the value of the button's variable is
changed from outside of the widget itself, as in the following example
(please note the difference in the checkbutton's appearance between the
toggle() and toggle2() functions):

###############################
from Tkinter import *

root=Tk()
v = StringVar(value='2')

cb = Checkbutton(root, text='foobar', variable=v,
                    onvalue='1', offvalue='0', tristatevalue='2')
cb.pack(padx=100, pady=100)

def toggle(ev):
    v.set('2')# tristatevalue -> third state is displayed
cb.bind('<F1>', toggle)

def toggle2(ev):
    v.set('3')# undefined value -> button appears unchecked
cb.bind('<F2>', toggle2)

root.mainloop()
###############################

Best regards

Michael

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