I have a set of combo boxes that the user will use to set parameters in a Ham radio. I am trying to 'set' the default values for each combo box when the user asks for a new clean file.
I have saved a dictionary in a json file which contains all the default parameter values. The function opens and loads the json file into a dictionary. Then I want to loop thru each combo box and 'set' its value from the dictionary. My code produces an error, "An error occurred: 'str' object has no attribute 'set' " when attempting to 'set' the combobox value.
I'm building the combobox name with a combination of the text "combobox_" and concatenating the three number key string and setting a string variable. Then using that variable with the 'set' method to change the combobox value. I've replaced the variable with an actual combobox name, and it works fine. So, it doesn't like my variable. Is there a way to loop thru the combobox widgets and set the value for each one?
def new_file() is called from a button to return combobox values to default. I've limited this code to 2 combo boxes. There are 153 in total.
# Load json file ==================
def load_json_file(file_path): # Load the JSON file with the menu data
print(f"Loading data file '{file_path}'...")
try:
with open(file_path, 'r') as file:
data = json.load(file)
print(f"Loaded data file successfully.")
return data
except FileNotFoundError:
print(f"Error: The file '{file_path}' was not found.")
except json.JSONDecodeError as e:
print(f"Error: Failed to decode JSON. {e}")
except Exception as e:
print(f"An unexpected error occurred: {e}")
# load default values to combo boxes
def new_file():
global Menu_Value
# Retrieve data file
file_path = 'Default_Menu_Values.991A'
data = load_json_file(file_path)
# Load Combo Boxes with Default Menu Values
try:
for m in range (1, 2):
ID = f"{m:03}"
Menu_Value = str(data.get(ID))
combo = "combobox_" + str(ID)
combo.set(Menu_Value) # Error happens here
except Exception as e:
print(f"An error occurred: {e}")
# code from main ==========================
# Create Combo Boxes ====================
# label_001 ==============================================
label_001 = ttk.Label(main_frame, text="001 - AGC FAST DELAY (msec)", width=35, relief="raised")
label_001.grid(row=0, column=0, padx=5, pady=5, ipadx=1, ipady=1, sticky="e")
# Combobox 001 ===========================================
values_001 = list(range(20, 4020, 20))
combobox_001 = ttk.Combobox(main_frame, width=15, values=values_001)
combobox_001.set("300 msec")
# Restrict selection to the drop-down list
combobox_001.state(["readonly"])
combobox_001.grid(row=0, column=1, padx=5, pady=5, sticky="w")
# label_002 ====================================================
label_002 = ttk.Label(main_frame, text="002 - AGC MID DELAY (msec)", width=35, relief="raised")
label_002.grid(row=1, column=0, padx=5, pady=5, ipadx=1, ipady=1, sticky="e")
# Combobox 002 ==================================================
values_002 = list(range(20, 4020, 20))
combobox_002 = ttk.Combobox(main_frame, width=15, values=values_002)
combobox_002.set("700 msec")
# Restrict selection to the drop-down list
combobox_002.state(["readonly"])
combobox_002.grid(row=1, column=1, padx=5, pady=5, sticky="w")
I have a set of combo boxes that the user will use to set parameters in a Ham radio. I am trying to 'set' the default values for each combo box when the user asks for a new clean file.
I have saved a dictionary in a json file which contains all the default parameter values. The function opens and loads the json file into a dictionary. Then I want to loop thru each combo box and 'set' its value from the dictionary. My code produces an error, "An error occurred: 'str' object has no attribute 'set' " when attempting to 'set' the combobox value.
I'm building the combobox name with a combination of the text "combobox_" and concatenating the three number key string and setting a string variable. Then using that variable with the 'set' method to change the combobox value. I've replaced the variable with an actual combobox name, and it works fine. So, it doesn't like my variable. Is there a way to loop thru the combobox widgets and set the value for each one?
def new_file() is called from a button to return combobox values to default. I've limited this code to 2 combo boxes. There are 153 in total.
# Load json file ==================
def load_json_file(file_path): # Load the JSON file with the menu data
print(f"Loading data file '{file_path}'...")
try:
with open(file_path, 'r') as file:
data = json.load(file)
print(f"Loaded data file successfully.")
return data
except FileNotFoundError:
print(f"Error: The file '{file_path}' was not found.")
except json.JSONDecodeError as e:
print(f"Error: Failed to decode JSON. {e}")
except Exception as e:
print(f"An unexpected error occurred: {e}")
# load default values to combo boxes
def new_file():
global Menu_Value
# Retrieve data file
file_path = 'Default_Menu_Values.991A'
data = load_json_file(file_path)
# Load Combo Boxes with Default Menu Values
try:
for m in range (1, 2):
ID = f"{m:03}"
Menu_Value = str(data.get(ID))
combo = "combobox_" + str(ID)
combo.set(Menu_Value) # Error happens here
except Exception as e:
print(f"An error occurred: {e}")
# code from main ==========================
# Create Combo Boxes ====================
# label_001 ==============================================
label_001 = ttk.Label(main_frame, text="001 - AGC FAST DELAY (msec)", width=35, relief="raised")
label_001.grid(row=0, column=0, padx=5, pady=5, ipadx=1, ipady=1, sticky="e")
# Combobox 001 ===========================================
values_001 = list(range(20, 4020, 20))
combobox_001 = ttk.Combobox(main_frame, width=15, values=values_001)
combobox_001.set("300 msec")
# Restrict selection to the drop-down list
combobox_001.state(["readonly"])
combobox_001.grid(row=0, column=1, padx=5, pady=5, sticky="w")
# label_002 ====================================================
label_002 = ttk.Label(main_frame, text="002 - AGC MID DELAY (msec)", width=35, relief="raised")
label_002.grid(row=1, column=0, padx=5, pady=5, ipadx=1, ipady=1, sticky="e")
# Combobox 002 ==================================================
values_002 = list(range(20, 4020, 20))
combobox_002 = ttk.Combobox(main_frame, width=15, values=values_002)
combobox_002.set("700 msec")
# Restrict selection to the drop-down list
combobox_002.state(["readonly"])
combobox_002.grid(row=1, column=1, padx=5, pady=5, sticky="w")
1 Answer
Reset to default 0The problem is that you're trying to use a string variable, combo, as if it were a combobox object.
What you can do is store your comboboxes objects in a dictionary and then access them by their keys.
Try this code, it should fix the problem. You can run it to confirm.
import tkinter as tk
from tkinter import ttk
import json
def load_json_file(file_path):
print(f"Loading data file '{file_path}'...")
try:
with open(file_path, 'r') as file:
data = json.load(file)
print(f"Loaded data file successfully.")
return data
except FileNotFoundError:
print(f"Error: The file '{file_path}' was not found.")
except json.JSONDecodeError as e:
print(f"Error: Failed to decode JSON. {e}")
except Exception as e:
print(f"An unexpected error occurred: {e}")
def new_file():
global combobox_dict
file_path = 'Default_Menu_Values.991A'
data = load_json_file(file_path) # dictionary with the default values
try:
for m in range(1, 3):
ID = f"{m:03}" # key of the value in dictionary
Menu_Value = str(data.get(ID)) # default value for each combobox as string
combobox_dict[f"combobox_{ID}"].set(Menu_Value) # combobox widget stored in the combobox_dict
except Exception as e:
print(f"An error occurred: {e}")
# Main window setup
root = tk.Tk()
main_frame = ttk.Frame(root)
main_frame.pack(padx=10, pady=10)
# Create Combo Boxes and store them in a dictionary
combobox_dict = {} # store the combobox widgets
label_001 = ttk.Label(main_frame, text="001 - AGC FAST DELAY (msec)", width=35, relief="raised")
label_001.grid(row=0, column=0, padx=5, pady=5, ipadx=1, ipady=1, sticky="e")
values_001 = list(range(20, 4020, 20))
combobox_001 = ttk.Combobox(main_frame, width=15, values=values_001)
combobox_001.set("300")
combobox_001.state(["readonly"])
combobox_001.grid(row=0, column=1, padx=5, pady=5, sticky="w")
combobox_dict["combobox_001"] = combobox_001 # store the combobox_001 widget
label_002 = ttk.Label(main_frame, text="002 - AGC MID DELAY (msec)", width=35, relief="raised")
label_002.grid(row=1, column=0, padx=5, pady=5, ipadx=1, ipady=1, sticky="e")
values_002 = list(range(20, 4020, 20))
combobox_002 = ttk.Combobox(main_frame, width=15, values=values_002)
combobox_002.set("700")
combobox_002.state(["readonly"])
combobox_002.grid(row=1, column=1, padx=5, pady=5, sticky="w")
combobox_dict["combobox_002"] = combobox_002 # store the combobox_002 widget
new_file_button = ttk.Button(main_frame, text="New File", command=new_file)
new_file_button.grid(row=2, column=0, columnspan=2, pady=10)
# Example JSON file content (for testing)
with open('Default_Menu_Values.991A', 'w') as f:
json.dump({"001": "100", "002": "500"}, f)
root.mainloop()