Tkinter OptionMenu unique identifiers to duplicate display values

Question

Using this question as a base - Tkinter OptionMenu DisplayOptions and Assignment Values

Answer code here:

import Tkinter as tk
master = tk.Tk()
variable = tk.StringVar(master)
options = {"one": 1, "two": 2}
tk.OptionMenu(master, variable, *options.keys()).pack()
...
wanted = options[variable.get()]

However, I intend for my integer values to work as unique identifiers, even though the strings may be the same. See the following.

# this will overwrite the "a" value to be 3
# the first entry will be lost
options = {"a": 1, "b": 2, "a": 3}

# so instead switch the order...
options = {1: "a", 2: "b", 3: "a"}
# then we can use values() to provide the options
tk.OptionMenu(master, variable, *options.values()).pack()
...
# but now how do I replace this line 
# to get the correct identifier for the option chosen?
wanted = options[variable.get()]

Is it possible to have duplicate display text in the OptionMenu that links back to the correct unique identifiers?

How is the user supposed to know which one of those `a`s to select? This seems like a completely unusable UI design. — jasonharper, Jun 12 '20 at 13:38
upon selecting either `a`, more details should show, but that is assuming I can get the correct identifier. You could think of two people named `a` that the UI then shows more details such as address, phone number, etc — DoubleDouble, Jun 12 '20 at 13:43

score 1 · Answer 1 · answered Jun 13 '20 at 17:39

Below is how I solved this problem. I extend my own StringVar class along with re-implementing the OptionMenu class. I put this in their own source file, I wouldn't suggest "writing over" the tk implementation.

import tkinter as tk

class LinkedIntStringVar(tk.StringVar):
    '''Takes a dictionary of int to strings. default 'get' function
        will return strings as normal, but there is also special function for
        returning based on the integer values 'get_int'.
    Setting the variable requires using the integer value set in int_string_dict'''
    def __init__(self, master=None, int_string_dict=None, value=None, name=None):
        tk.StringVar.__init__(self, master, value, name)
        self.__int_string_dict = int_string_dict
        self.__current_int_value = 0

    def get_int(self):
        """Return value of variable as integer."""
        return self.__current_int_value

    def set(self, value):
        """Set the variable to VALUE."""
        string_value = self.__int_string_dict[value]
        self.__current_int_value = value
        super().set(string_value)

# No changes from tkinter's implementation here, I just like it to be available.
class _setit:
    """Internal class. It wraps the command in the widget OptionMenu."""
    def __init__(self, var, value, callback=None):
        self.__value = value
        self.__var = var
        self.__callback = callback
    def __call__(self, *args):
        self.__var.set(self.__value)
        if self.__callback:
            self.__callback(self.__value, *args)

# Changes to this class are commented below
class OptionMenu(tk.Menubutton):
    """OptionMenu which allows the user to select a value from a menu."""
    def __init__(self, master, variable, values, **kwargs): # removed 'value' from args
        """Construct an optionmenu widget with the parent MASTER, with
        the resource textvariable set to VARIABLE, the initially selected
        value VALUE, the other menu values VALUES and an additional
        keyword argument command."""
        kw = {"borderwidth": 2, "textvariable": variable,
              "indicatoron": 1, "relief": tk.RAISED, "anchor": "c",
              "highlightthickness": 2}
        tk.Widget.__init__(self, master, "menubutton", kw)
        self.widgetName = 'tk_optionMenu'
        menu = self.__menu = tk.Menu(self, name="menu", tearoff=0)
        self.menuname = menu._w
        # 'command' is the only supported keyword
        callback = kwargs.get('command')
        if 'command' in kwargs:
            del kwargs['command']
        if kwargs:
            raise tk.TclError('unknown option -'+kwargs.keys()[0])
        # Issues with the variables clashing, 
        # I personally just depend on the variable's value so it was easiest 
        # just to remove this unneeded portion (for my case)
        #menu.add_command(label=value,
        #         command=_setit(variable, value, callback))
        for v in values.keys(): # Change this line to handle dict instead of list
            # Change this line to set to the String value in the dict
            menu.add_command(label=values[v],
                     command=_setit(variable, v, callback))
        self["menu"] = menu

    def __getitem__(self, name): # No changes
        if name == 'menu':
            return self.__menu
        return tk.Widget.__getitem__(self, name)

    def destroy(self): # No changes
        """Destroy this widget and the associated menu."""
        tk.Menubutton.destroy(self)
        self.__menu = None

Below is a sample of how it can be used.

# import the custom classes
import tkinter as tk

master = tk.Tk()

options = { 0: 'None', 1: 'Test', 2: 'Example', 3: 'Test'}
variable = LinkedIntStringVar(master, int_string_dict=options)
variable.set(0)

option_menu = OptionMenu(master, variable, options,
                         command=lambda value, *args: print('Changed to', value)).pack()
tk.mainloop()

You will see the integer values returned in the callback. the string can be returned with variable.get() and the integer value can also be returned with variable.get_int()

Tkinter OptionMenu unique identifiers to duplicate display values

1 Answers1