获取绑定到Entry小部件的StringVar

Question

I'm writing a simple GUI program, and need to load default values from an ini file. I've given names to Entry widget and can get it with nametowidget method.

However, I can't find a way to access the StringVar bound to the entry widget and update it's value. Using debugger, I can see that StringVar objects dont have a tkinter master, and they dont appear in any widget children. So is what I'm trying to do possible ? Or is there a workaround ?

Below is the concerned function.

def load_data(data_file):
    """
    Read an ini file and update related values
    :param data_file:
    :return:
    """
    conf = configparser.ConfigParser()
    try:
        conf.read(data_file)
        for section in conf.sections():
            try:
                container = SECTIONS[section]
                for key in conf[section]:
                    widget = container.nametowidget(key)
                    widget.set(conf[section][key])
            except KeyError:
                pass
    except configparser.Error as e:
        print(e)

Answer 1

You can access the StringVar associated to a widget by widget["textvariable"] .

import tkinter as tk

root = tk.Tk()

a = tk.StringVar()
a.set(0)

b = tk.Entry(root,textvariable=a)
b.pack()

print (b["textvariable"])

root.mainloop()

Answer 2

Tkinter widgets have a getvar and setvar method which can be used to get and set the value of a variable by its name.

You can get the name of the variable associated with a widget using the cget method.

Example:

var = tk.IntVar()
entry = tk.Entry(..., textvariable=var)
...
varname = entry.cget("textvariable")
value = entry.getvar(varname)
entry.setvar(varname, value+1)