python

import reflex as rx

Form

Forms are used to collect user input. The rx.form component is used to group inputs and submit them together.

The form component's children can be form controls such as rx.input, rx.checkbox, rx.slider, rx.textarea, rx.radio_group, rx.select or rx.switch. The controls should have a name attribute that is used to identify the control in the form data. The on_submit event trigger submits the form data as a dictionary to the handle_submit event handler.

The form is submitted when the user clicks the submit button or presses enter on the form controls.

python

class FormState(rx.State):
    form_data: dict = {}

    @rx.event
    def handle_submit(self, form_data: dict):
        """Handle the form submit."""
        self.form_data = form_data


def form_example():
    return rx.vstack(
        rx.form(
            rx.vstack(
                rx.input(placeholder="First Name", name="first_name"),
                rx.input(placeholder="Last Name", name="last_name"),
                rx.hstack(
                    rx.checkbox("Checked", name="check"),
                    rx.switch("Switched", name="switch"),
                ),
                rx.button("Submit", type="submit"),
            ),
            on_submit=FormState.handle_submit,
            reset_on_submit=True,
        ),
        rx.divider(),
        rx.heading("Results"),
        rx.text(FormState.form_data.to_string()),
    )

# When using the form you must include a button or input with `type='submit'`.

# Using `name` vs `id`.

When using the `name` attribute in form controls like `rx.switch`, `rx.radio_group`, and `rx.checkbox`, these controls will only be included in the form data if their values are set (e.g., if the checkbox is checked, the switch is toggled, or a radio option is selected).

If you need these controls to be passed in the form data even when their values are not set, you can use the `id` attribute instead of name. The id attribute ensures that the control is always included in the submitted form data, regardless of whether its value is set or not.

# Video: Forms

Dynamic Forms

Forms can be dynamically created by iterating through state vars using rx.foreach.

This example allows the user to add new fields to the form prior to submit, and all fields will be included in the form data passed to the handle_submit function.

python

class DynamicFormState(rx.State):
    form_data: dict = {}
    form_fields: list[str] = ["first_name", "last_name", "email"]

    @rx.var(cache=True)
    def form_field_placeholders(self) -> list[str]:
        return [
            " ".join(w.capitalize() for w in field.split("_"))
            for field in self.form_fields
        ]

    @rx.event
    def add_field(self, form_data: dict):
        new_field = form_data.get("new_field")
        if not new_field:
            return
        field_name = new_field.strip().lower().replace(" ", "_")
        self.form_fields.append(field_name)

    @rx.event
    def handle_submit(self, form_data: dict):
        self.form_data = form_data


def dynamic_form():
    return rx.vstack(
        rx.form(
            rx.vstack(
                rx.foreach(
                    DynamicFormState.form_fields,
                    lambda field, idx: rx.input(
                        placeholder=DynamicFormState.form_field_placeholders[idx],
                        name=field,
                    ),
                ),
                rx.button("Submit", type="submit"),
            ),
            on_submit=DynamicFormState.handle_submit,
            reset_on_submit=True,
        ),
        rx.form(
            rx.hstack(
                rx.input(placeholder="New Field", name="new_field"),
                rx.button("+", type="submit"),
            ),
            on_submit=DynamicFormState.add_field,
            reset_on_submit=True,
        ),
        rx.divider(),
        rx.heading("Results"),
        rx.text(DynamicFormState.form_data.to_string()),
    )