Python gui validate entry widget Part 18

Python offers a variety of frameworks to work with GUI applications. Tkinter or Tk interface is one of the most widely used Python interface to build GUI based applications. There are applications that require validation of text fields to prevent invalid input from the user before the form is submitted. Python allows input validation by allowing variable tracing using a callback function. This function is called whenever an input is added/deleted to/from an Entry widget. Some applications validate input on form submission, but the following piece of code performs validation with every stroke of key from the keyboard.
In this video we can use get() and set () method to validate entry widget with messagebox.