Live Form

    <.form for={@form} phx-submit="save_phoenix"
  class="flex flex-col gap-space-lg w-full max-w-xl"
>
  <.combobox
    field={@form[:country]}
    class="combobox"
    translation={%Corex.Combobox.Translation{placeholder: "Country", empty: "No results"}}
    items={Corex.List.new([
      %{label: "France", value: "fra"},
      %{label: "Belgium", value: "bel"},
      %{label: "Germany", value: "deu"},
      %{label: "Netherlands", value: "nld"},
      %{label: "Switzerland", value: "che"},
      %{label: "Austria", value: "aut"}
    ])}
  >
    <:label>Country</:label>
    <:empty>No results</:empty>
    <:trigger><.heroicon name="hero-chevron-down" class="icon" /></:trigger>
    <:error :let={msg}>
      <.heroicon name="hero-exclamation-circle" class="icon" />
      {msg}
    </:error>
  </.combobox>
  <.action type="submit" class="button ui-accent">
    Submit
  </.action>
</.form>

  

    defmodule MyAppWeb.ComboboxFormLive do
  use MyAppWeb, :live_view

  def mount(_params, _session, socket) do
    phoenix_form =
      Phoenix.Component.to_form(%{"country" => ""}, as: :combobox_phoenix, id: "combobox-live-form-phoenix")

    {:ok, assign(socket, :phoenix_form, phoenix_form)}
  end

  def handle_event("save_phoenix", %{"combobox_phoenix" => params}, socket) do
    country = params["country"] || ""

    {:noreply,
     assign(
       socket,
       :phoenix_form,
       Phoenix.Component.to_form(%{"country" => country}, as: :combobox_phoenix, id: "combobox-live-form-phoenix")
     )}
  end
end

  

    <.form
  for={@strict_form}
 
  phx-change="validate_strict"
  phx-submit="save_strict"
  class="flex flex-col gap-space-lg w-full max-w-xl"
>
  <.combobox
    field={@strict_form[:country]}
    class="combobox"
    translation={%Corex.Combobox.Translation{placeholder: "Country", empty: "No results"}}
    clear_on_empty={true}
    items={Corex.List.new([
      %{label: "France", value: "fra"},
      %{label: "Belgium", value: "bel"},
      %{label: "Germany", value: "deu"},
      %{label: "Netherlands", value: "nld"},
      %{label: "Switzerland", value: "che"},
      %{label: "Austria", value: "aut"}
    ])}
  >
    <:label>Country</:label>
    <:empty>No results</:empty>
    <:trigger><.heroicon name="hero-chevron-down" /></:trigger>
    <:clear_trigger><.heroicon name="hero-backspace" class="icon" /></:clear_trigger>
    <:error :let={msg}>
      <.heroicon name="hero-exclamation-circle" class="icon" />
      {msg}
    </:error>
  </.combobox>
  <.action type="submit" class="button ui-accent">Submit</.action>
</.form>

  

    defmodule MyAppWeb.ComboboxFormLive do
  use MyAppWeb, :live_view

  def mount(_params, _session, socket) do
    ecto_form =
      %MyApp.Forms.Travel{}
      |> MyApp.Forms.Travel.changeset_validate(%{})
      |> Phoenix.Component.to_form(as: :combobox_ecto, id: "combobox-live-form-ecto")

    {:ok, assign(socket, :ecto_form, ecto_form)}
  end

  def handle_event("validate", %{"combobox_ecto" => params}, socket) do
    changeset =
      %MyApp.Forms.Travel{}
      |> MyApp.Forms.Travel.changeset_validate(params)
      |> Map.put(:action, :validate)

    {:noreply,
     assign(
       socket,
       :ecto_form,
       Phoenix.Component.to_form(changeset,
         action: :validate,
         as: :combobox_ecto,
         id: "combobox-live-form-ecto"
       )
     )}
  end

  def handle_event("save", %{"combobox_ecto" => params}, socket) do
    case MyApp.Forms.Travel.changeset_validate(%MyApp.Forms.Travel{}, params) do
      %Ecto.Changeset{valid?: true} = changeset ->
        _data = Ecto.Changeset.apply_changes(changeset)

        {:noreply,
         assign(
           socket,
           :ecto_form,
           Phoenix.Component.to_form(
             MyApp.Forms.Travel.changeset_validate(%MyApp.Forms.Travel{}, params),
             as: :combobox_ecto,
             id: "combobox-live-form-ecto"
           )
         )}

      changeset ->
        {:noreply,
         assign(
           socket,
           :ecto_form,
           Phoenix.Component.to_form(changeset,
             action: :insert,
             as: :combobox_ecto,
             id: "combobox-live-form-ecto"
           )
         )}
    end
  end
end

  

    defmodule MyApp.Forms.Travel do
  use Ecto.Schema
  import Ecto.Changeset

  embedded_schema do
    field :country, :string
  end

  def changeset(form, attrs \\ %{}) do
    form
    |> cast(attrs, [:country])
    |> validate_required([:country])
  end

  def changeset_validate(form, attrs \\ %{}) do
    form
    |> cast(attrs, [:country])
    |> validate_required([:country], message: "can't be blank")
  end
end