Django Forms

Django Forms are used to collect input from users, check if the input is correct and process the data.

• Gather information through form fields such as text, email, or password.
• Automatically validate the data before processing.
• Can save the cleaned data to the database when needed.
• Provide a clean way to handle user input in web applications.

Syntax

field_name = forms.FieldType(**options)

• field_name: Name of the form field.
• FieldType: Type of the field (e.g., CharField, EmailField, IntegerField).
• options: Optional keyword arguments such as max_length, required, initial, label, etc.

Creating a Simple Django Form

Before creating forms, ensure that a Django project and app are already set up. Creating a form in Django is similar to creating a model, as it requires specifying the fields and their types.

To create a form, create a "forms.py" file in app folder:

Render Django Forms

Django form fields have several built-in methods to ease the work of the developer but sometimes one needs to implement things manually for customizing User Interface (UI). A form comes with 3 in-built methods that can be used to render Django form fields. 

• {{ form.as_table }} will render them as table cells wrapped in <tr> tags
• {{ form.as_p }} will render them wrapped in <p> tags
• {{ form.as_ul }} will render them wrapped in <li> tags

To render this form into a view, Create a home_view in views.py:

After defining the view, configure the URL patterns to connect it. Next, create an instance of the form class inside the view and set up a templates/home.html file to render the form and display it to users.

Visit: http://localhost:8000/

Create Django Form from Models

Django ModelForm is a class used to directly convert a model into a Django form. In database-driven applications, forms often map closely to Django models.

Once the project is ready, create a model in geeks/models.py:

To create a form directly for this model, in geeks/forms.py:

By visiting http://127.0.0.1:8000/, the form will be displayed and users can input data according to the fields defined in the model.

Advantages of Using Django Forms

Django Forms provide a high-level interface for handling user input, rendering form elements, validating data, and processing submissions securely.

• Automatic field generation: Form fields are created and mapped to appropriate HTML input elements, reducing manual coding.
• Easy rendering: Django can render complete forms using helpers like {{ form.as_p }}, simplifying template integration.
• Built-in validation: Ensures submitted data is clean, complete, and correctly formatted without extra logic.
• Smooth model integration: Works seamlessly with Django models, enabling quick data saving and retrieval.
• Strong security: Includes CSRF protection and sanitizes input to prevent malicious data submission.
• Better maintainability: Centralizes form logic, making forms easier to update and debug as the application grows.

Django Forms Data Types and Fields List

The most important part of a form and the only required part is the list of fields it defines. Fields are specified by class attributes. Here is a list of all Form Field types used in Django

Note: NullBooleanField (a boolean field that allowed True, False, or NULL) is deprecated. Use BooleanField(null=True, blank=True) instead.

Core Field Arguments

Core Field arguments are parameters provided to each field in a model to apply constraints or impart specific characteristics. For example, adding required=False to a CharField allows the field to be left blank by the user.

Each Field class constructor accepts at least these core arguments. Some Field classes may also accept additional, field-specific arguments, but the following are always supported: