Display of Django Forms select defaults and selected values

Django's forms and models are just as awesome. He has two functions, one is to generate form forms, and also to validate form forms.

Here is a general case of the beam that is often used when generating form forms to set default values.

1. Set the default selected option when you need to generate select by default.

In the django/forms/widgets.py file

Here's a _empty_value field that sets the default value.

When creating a form, configure the default options:

2. When querying the data from the database to the front-end display, how to select the specified option on the front-end.

The ID of the selected authors that is queried in the database is passed into the Bookform class as a parameter, and an object is generated, which is passed to the front end to show the selected value.

Display of Django Forms select defaults and selected values