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Combobox Widget in Tkinter

The Combobox widget is a combination of a drop-down list and an input field. In tkinter, the Combobox widget is available through the ttk module, which provides access to the Tk themed widget set.

Here's a step-by-step tutorial to guide you on using the Combobox widget in tkinter:

Combobox Widget in Tkinter

  1. Setting up the basic GUI with Tkinter:

    Start with a basic window using tkinter.

    import tkinter as tk
from tkinter import ttk

root = tk.Tk()
root.title("Combobox in Tkinter")
root.geometry("300x200")

  2. Adding the Combobox widget:

    Use the ttk.Combobox to create the combobox widget.

    # Create a label
label = ttk.Label(root, text="Choose a country:")
label.pack(pady=10)

# Create the Combobox
countries = ["USA", "Canada", "Australia", "India", "UK", "Germany"]
country_combobox = ttk.Combobox(root, values=countries)
country_combobox.pack(pady=10)

  3. Setting and getting values from Combobox:

    • To set a default value:

      country_combobox.set("USA")

    • To retrieve the currently selected value:

      def get_selected_country():
    selected_country = country_combobox.get()
    print(f"Selected Country: {selected_country}")

# Button to trigger value retrieval
btn = ttk.Button(root, text="Get Selected Country", command=get_selected_country)
btn.pack(pady=20)

  4. Run the main loop:

    root.mainloop()

Combining the code snippets above and running the script will present a tkinter window with a Combobox widget. The Combobox will have a list of countries. By clicking the "Get Selected Country" button, the selected country's name will be printed in the console.

Note:

The Combobox also provides additional functionalities such as:

  • state option to make it read-only.
  • Binding to virtual events like <<ComboboxSelected>> to execute a function whenever a new value is selected from the drop-down list.

To implement a read-only Combobox, you can use:

country_combobox['state'] = 'readonly'

To bind to the selection event:

def on_value_change(event):
    selected_country = country_combobox.get()
    print(f"Selected Country: {selected_country}")

country_combobox.bind("<<ComboboxSelected>>", on_value_change)

You can incorporate these additional functionalities based on the needs of your application.

  1. How to use ComboBox in Tkinter:

    • Description: Use a ComboBox (Dropdown) in Tkinter to provide users with a list of options from which they can choose.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

def on_select(event):
    selected_value = combo.get()
    print(f"Selected Value: {selected_value}")

root = tk.Tk()

# Create a ComboBox
options = ["Option 1", "Option 2", "Option 3"]
combo = ttk.Combobox(root, values=options)
combo.grid(row=0, column=0, padx=10, pady=10)
combo.bind("<<ComboboxSelected>>", on_select)

root.mainloop()

  2. Creating dropdown menus with Tkinter ComboBox:

    • Description: Use Tkinter ComboBox to create dropdown menus with a list of options.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

root = tk.Tk()

# Create a ComboBox for a dropdown menu
options = ["Option 1", "Option 2", "Option 3"]
combo = ttk.Combobox(root, values=options)
combo.grid(row=0, column=0, padx=10, pady=10)

root.mainloop()

  3. Customizing options in Tkinter ComboBox:

    • Description: Customize the appearance and behavior of options in a Tkinter ComboBox.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

root = tk.Tk()

# Customize ComboBox options
combo = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"], font=("Arial", 12), state="readonly")
combo.grid(row=0, column=0, padx=10, pady=10)

root.mainloop()

  4. Handling events with Tkinter ComboBox:

    • Description: Handle events (e.g., selection) with Tkinter ComboBox using the bind method.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

def on_select(event):
    selected_value = combo.get()
    print(f"Selected Value: {selected_value}")

root = tk.Tk()

# Handle events with ComboBox
combo = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"])
combo.grid(row=0, column=0, padx=10, pady=10)
combo.bind("<<ComboboxSelected>>", on_select)

root.mainloop()

  5. Adding items dynamically to Tkinter ComboBox:

    • Description: Add items dynamically to a Tkinter ComboBox during runtime.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

def add_item():
    new_item = entry.get()
    combo['values'] = combo['values'] + (new_item,)

root = tk.Tk()

# Add items dynamically to ComboBox
combo = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"])
combo.grid(row=0, column=0, padx=10, pady=10)

entry = tk.Entry(root)
entry.grid(row=1, column=0, padx=10, pady=10)

add_button = tk.Button(root, text="Add Item", command=add_item)
add_button.grid(row=1, column=1, padx=10, pady=10)

root.mainloop()

  6. Tkinter ComboBox with default values:

    • Description: Set default values for a Tkinter ComboBox.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

root = tk.Tk()

# Set default value for ComboBox
combo = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"], state="readonly")
combo.set("Option 1")
combo.grid(row=0, column=0, padx=10, pady=10)

root.mainloop()

  7. Bind function to ComboBox selection in Tkinter:

    • Description: Bind a function to the selection event of a Tkinter ComboBox.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

def on_select(event):
    selected_value = combo.get()
    print(f"Selected Value: {selected_value}")

root = tk.Tk()

# Bind function to ComboBox selection
combo = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"])
combo.grid(row=0, column=0, padx=10, pady=10)
combo.bind("<<ComboboxSelected>>", on_select)

root.mainloop()

  8. Setting width and height of Tkinter ComboBox:

    • Description: Set the width and height of a Tkinter ComboBox.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

root = tk.Tk()

# Set width and height for ComboBox
combo = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"], width=15, height=5, state="readonly")
combo.grid(row=0, column=0, padx=10, pady=10)

root.mainloop()

  9. Working with ComboBox in Tkinter forms:

    • Description: Use Tkinter ComboBox in forms to allow users to select options from predefined choices.
    • Code Example:
      import tkinter as tk
from tkinter import ttk

def submit_form():
    selected_option = combo.get()
    print(f"Form submitted with option: {selected_option}")

root = tk.Tk()

# ComboBox in a form
combo = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"], state="readonly")
combo.grid(row=0, column=0, padx=10, pady=10)

submit_button = tk.Button(root, text="Submit", command=submit_form)
submit_button.grid(row=1, column=0, pady=10)

root.mainloop()
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