Calling A Tk Instance From Another Tk Instance Causes Issue Setting Textvariables

I have built a simple user dropdown menu using Tkinter and ttk. I use textvariable.set() to set a default value for the window on loading. Everything works great. Code is below. fr

Solution 1:

Having two Tk instances confuses it. If you want things displayed in a separate top-level window, call Toplevel() instead and things will work.

def load_dropdown():
    parent =Toplevel()  # <- change to this
    myvalue = StringVar()
    ...

Solution 2:

You cannot use more than once instance of Tk in a tkinter application. You are observing one of the negative side-effects of trying to do so.

If you need a second window, create an instance of Toplevel rather than a second instance of Tk.

Solution 3:

In tkinter you only ever create one mainloop which is done by root = Tk()

This is your default window. Your example will work if you get rid of the second creation of parent.

To create more windows use new_window = TopLevel()

There is a lot of good documentation on tkinter, make use of it and it will take you far :)

http://effbot.org/tkinterbook/toplevel.htm

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/toplevel.html

http://www.tkdocs.com/tutorial/windows.html

https://docs.python.org/2/library/tkinter.html