Rails：未定义的方法错误无法使用 attr_accessor 修复

Question

I have created a very simple model called Discussion and one of the columns is a boolean called resolved. The idea being that once a discussion item has been resolved that value is set to true.

On the edit form, I tried to put in some logic based on the value of that field.

<%= form_for(@discussion) do |d| %>
    ...
<% if d.resolved == "true" %>
    <p>The discussion is resolved</p>
<% else %>
    <p>The discussion is not resolved</p>
<% end %>
<% end %>

However, I'm getting an error message

undefined method `resolved' for #<ActionView::Helpers::FormBuilder:0x00000101674678>

I tried adding an attr_accessor line to my model but that didn't do anything for me either. I'm not sure what I have to do to fix this. I'm pretty new to rails, so I'm sure that whatever the problem is it's probably pretty simple to fix, but I just don't get it. Thanks.

Answer 1

Because d represent an instance of the form builder, you want

<% if @discussion.resolved %>

If resolved is represented as a "boolean" in ActiveRecord.

Answer 2

every boolean column represents as predicate, so you can use:

if @discussion.resolved?
...
end

Answer 3

What you're looking for is the resolved? method.

<% if @discussion.resolved? %>

which is auto-generated for boolean columns.