我如何获得我刚刚通过 form_with 创建的 model 的 ID，基本上从一个 controller 到 Rails 中的另一个

Question

Sort of new in rails so i might be doing things the wrong way show.html.erb:

<% @feature.each do |p| %>
    <br>
    <h1><%= p.name %></h1>
   
    <%= p.unit_price %>
    <%= render partial: "shared/featureuse_form", locals: {feat_use: @feat_use , feature: p} %>
    <%= button_to'Change' , feature_use_path(1) , :class => 'btn btn-primary'  ,method: :delete %>

<% end %>

Right here in feature_use_path how do i get an id to pass it in order to make a delete button as i havent even created the model yet or its saved in its own controller should

_featureuse_form.html.erb:

<%= form_with model: feat_use do |f| %>
    <%= f.number_field :total_units ,value: feature.max_unit_limit  %>
    <%= f.hidden_field :feature_id, value: feature.id %>
    <%= f.hidden_field :usage_id, value: current_user.usage.id %>
    <%= f.submit "confirm", id: "button"%> 
<% end %>

Plans Controller

class PlansController < ApplicationController

    before_action :authenticate_user!
    def index
        @plan = Plan.all
    end

    def show

        @plan = Plan.find(params[:id])
        @feature = @plan.features

        @feat_use = FeatureUse.new
    end
end
class FeatureUsesController < ApplicationController

  def create
        feature_use = FeatureUse.new(feature_use_params)
        feature_use.total_units = params[:feature_use][:total_units]
        feature_use.feature_id = params[:feature_use][:feature_id]
        user = current_user.usage
        feature_use.usage_id = user.id
        feature_use.save
        
    end

end

Answer 1

You're right that you can't create a button ( method: :delete or otherwise) that relies on a record that doesn't yet exist.

Usually, a button like this would only be relevant to existing records anyway.

So, it's common to see an if statement like this:

<% if @feature_use.persisted? %>
  <%= button_to 'Change' , feature_use_path(@feature_use.id) , :class => 'btn btn-primary', method: :delete %>
<% end %>

.persisted? returns false if the record is new and un-saved.