Whenever I use an f.select statement to determine assignment_id(or student_id), and I should
get a validation error, I
get this error instead of the validation message:
You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.collect
Extracted source (around line #11):
8: </p>
9: <p>
10: <%= f.label 'Assignment:' %><br />
11: <%= f.select(:assignment_id, @assignments.collect {|p| [p.ass_num, p.id]})%>
12: </p>
13: <p>
14: <%= f.label 'First Student:' %><br />
My grades model:
class Grade < ActiveRecord::Base
has_and_belongs_to_many :students
belongs_to :assignment
validates_presence_of :score, :assignment_id, :student_id
validates_numericality_of :score, :greater_than_or_equal_to => 0,
:less_than_or_equal_to => 100, :allow_nil => true
validates_uniqueness_of :student_id, :scope => :assignment_id
end
If I use a text_field, I don't
get the error... but there's far too many students for that.
Neither @assignments nor @students are nil.
Any suggestions?
