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Python GUI Programming with Tkinter
book

Python GUI Programming with Tkinter

by Alan D. Moore
May 2018
Beginner to intermediate content levelBeginner to intermediate
452 pages
11h 26m
English
Packt Publishing
Content preview from Python GUI Programming with Tkinter

Requiring data

All of our fields are required, so let's start with a basic Entry widget that requires data. We can use these for fields: Technician and Seed sample.

Add the following code under the ValidatedMixin class:

class RequiredEntry(ValidatedMixin, ttk.Entry):

    def _focusout_validate(self, event):
        valid = True
        if not self.get():
            valid = False
            self.error.set('A value is required')
        return valid

There's no keystroke validation to do here, so we just need to create _focusout_validate(). If the entered value is empty, we just set an error string and return False.

That's all there is to it!

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Publisher Resources

ISBN: 9781788835886Supplemental Content