Referencing a field value in a Phoenix form

Question

In a Phoenix .eex/.leex form created with <%= f = form_for @changeset…, is there a way to reference one of the field values in a CSS class definition?

For example, I’d like to hide a div element if field1's value is “”. This is the code that I drafted that doesn't seem to work.

<div class= <%= if :field1 == "" do %>
                 "hidden"
            <% else %>
                 " "
             <% end %>

Answer 1

You can use Ecto.Changeset.get_field/3, Ecto.Changeset.get_change/3 or just go for @changeset.data.field1.

Check the docs for the differences between those three and put a temporary <%= inspect @changeset %> inside your form to see what data and changes are all about.

So one way of doing what you want is:

<div class="<%= if @changeset.data.value1 == "", do: "hidden", else: "" %>">

(Notice that I've put the <%= ... %> tags inside the double qoutes.)