First argument in form cannot contain nil or be empty

Question

Hello I am doing Rail Development track and now I am on building a todo list. I came across a problem that I couldn't solve.

I am now in editing todo item part.

Firstly, I had

    def url_options
      { todo_list_id: params[:todo_list_id] }.merge(super)
    end

However, it doesn't work for me. Therefore, I still have to add@todo_list when I would like to make a link for view, as below:

<ul class="todo_items">
        <% @todo_list.todo_items.each do |todo_item| %>
        <li id="<%= dom_id(todo_item) %>">
            <%= todo_item.content %>
            <%= link_to "Edit", edit_todo_list_todo_item_path(@todo_list, todo_item) %>
        </li>
        <% end %>

Why does this happen?

======

However, the problem can be solved. I now came across another issue which I am not able to resolve.

I had my edit.html.erb:

<%= form_for [@todo_list, @todo_item] do |form| %>

  <% if @todo_item.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@todo_item.errors.count, "error") %> prohibited this todo item from being saved:</h2>

      <ul>
      <% @todo_item.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>


    <%= form.label :content %>
    <%= form.text_field :content %>

    <%= form.submit "Save" %>
<%end%>

and defined edit in my controller

def edit 
      @todo_list = TodoList.find(params[:todo_list_id])
      @todo_item = todo_list.todo_items.find(params[:id])
    end

However, it just kept telling me that <font color="red">"ActionView::Template::Error: First argument in form cannot contain nil or be empty"

I have been doing researched for couple hours but couldn't find anything wrong. Please help me, thank you !

Answer 1 · 2015-01-18T15:48:03Z

January 18, 2015 3:48pm

Hello guys, I am a moron and I figure out what happened.

I just put

def edit 
      @todo_list = TodoList.find(params[:todo_list_id])
      @todo_item = @todo_list.todo_items.find(params[:id])
    end

  def url_options
      { todo_list_id: params[:todo_list_id] }.merge(super)
  end

in my create method, no wonder it doesn't work....

Thank you guys. I still feel thrilled when I found the mistake.

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Roy Huang

Roy Huang

First argument in form cannot contain nil or be empty

1 Answer

Roy Huang

Roy Huang