Creating Interactive Drop-Down Combo Boxes with Tkinter and ttkbootstrap for Modern UIs

Creating Interactive Drop-Down Combo Boxes with Tkinter and ttkbootstrap for Modern UIs

When building user interfaces in Python, one of the most essential tools to consider is the combination of Tkinter and its extension ttkbootstrap. Tkinter is a popular library for creating desktop applications, and ttkbootstrap extends Tkinter’s native widgets with modern, sleek themes. One commonly used widget is the combo box, which allows the user to select an option from a drop-down list. This article will guide you through the process of creating and using combo boxes with Tkinter and ttkbootstrap

Original Article + Source Codes

• An Introduction to Python GUI Design with ttkbootstrap and Tkinter

Why Use Drop Down Combo Boxes?

Drop-down combo boxes are a useful UI component because they allow users to select from a list of options without cluttering the interface. These controls are especially valuable when you have a limited set of valid options or want to save space. With a combo box, you can provide the user with a list while keeping the interface clean and intuitive.

Setting Up Your Environment

Before diving into coding, let’s ensure you have the right tools installed. You’ll need Python and Tkinter, and it’s highly recommended to install ttkbootstrap for enhanced widgets and themes.

pip install ttkbootstrap

Creating a Basic Drop-Down Combo Box

Let’s begin by creating a simple Tkinter window with a combo box using ttkbootstrap.

First we have to create a list of options that will be used to populate the dropdown menu. Here we will be simulating standard baudrates for serial communications so our list will be.

options = ['1200','2400','4800','9600']

Now we create a simple drop down combo box using the below code.

import ttkbootstrap

root = ttkbootstrap.Window(themename = 'darkly')

root.title('Hello World') 
root.geometry('400x400') # width x height

options = ['1200','2400','4800','9600']


my_combo = ttkbootstrap.Combobox(value = options)# populate the combobox

my_combo.pack(pady = 50)

root.mainloop()

value=options provides the list of options (the baud rates) as the dropdown list for the combo box.

On running this code ,You will get the following output.

Creating Drop-Down Combo Boxes with Tkinter and ttkbootstrap

Now the above code does not do anything.Now we have to get the selected value in the code and use it. For that you have to bind the combobox to an event .so when the value is selected the event is triggered andcontrol of the code goes there.

Here is the full code for that .

import ttkbootstrap

def click_bind(e):
    print(my_combo.get())

root = ttkbootstrap.Window(themename = 'darkly')

root.title('Hello World') 
root.geometry('400x400') # width x height

options = ['1200','2400','4800','9600']


my_combo = ttkbootstrap.Combobox(value = options)

my_combo.pack(pady = 50)

my_combo.bind('<<ComboboxSelected>>',click_bind)


root.mainloop()

Binding the <<ComboboxSelected>> event to the click_bind function connects the event of selecting an item from the combo box to a custom action defined in the function.

In Tkinter, the bind() method is used to link a specific event (in this case, <<ComboboxSelected>>) to a handler function (here, click_bind). When the user selects an option from the combo box, the <<ComboboxSelected>> event is triggered, and Tkinter automatically calls the click_bind function.

The function receives the event object as a parameter, allowing it to execute any code based on the user’s selection, such as retrieving the selected value with get() and performing additional actions like updating the UI or printing the value to the console. This mechanism enables the interface to respond interactively to user input.

The <<ComboboxSelected>> event in Tkinter is triggered whenever a user selects an item from a combo box (or when the selection changes). This event is bound to a specific function using the bind() method, allowing you to execute custom actions in response to the selection.

When a selection occurs, the event passes an event object to the bound function, which can be used to retrieve the currently selected value from the combo box. This is typically done using the get() method of the Combobox widget.