I am trying to use the invoke method of a ttk.Button, as shown at TkDocs (look at "The Command Callback"), but I keep getting this error:
AttributeError: 'NoneType' object has no attribute 'invoke'
So, I tried this in the Interactive Shell:
ActivePython 3.1.1.2 (ActiveState Software Inc.) based on
Python 3.1.1 (r311:74480, Aug 17 2009, 12:30:13) [MSC v.1500 32 bit (Intel)] on
win32
>>> from tkinter import *
>>> import tkinter.ttk as ttk
>>> root = Tk()
>>> button = ttk.Button(root, text="Test").grid(row=0, column=0)
>>> print(button)
None
Which shows that ttk.Button returns None.
Is ttk.Button meant to return None. And, if so, why does TkDocs say that there is an invoke method?