Rails 4-验证不适用于模型

Question

I have a model called RateIndex :

class RateIndex < ActiveRecord::Base
  belongs_to :user
  belongs_to :car

  validates :name,        :presence => true
  validates :car_name,    :presence => true
  validates :description, :presence => true
  ...
end

The controller is rate_indices_controller.rb

class RateIndicesController < ApplicationController
  def new
    @rate_index = RateIndex.new
  end
  ...

And the form:

<%= form_for(@rate_index) do |f| %>
  <% if @rate_index.errors.any? %>
    <div id="error_explanation">
      <h3><%= "#{pluralize(@rate_index.errors.count, "error")} prohibited this game from being saved:" %></h3>
      <ul>
        <% @rate_index.errors.full_messages.each do |msg| %>
          <li><%= msg %></li>
        <% end %>
      </ul>
    </div>
  <% end %>
  ...

But when I send the empty form, there are no validation errors displayed... I've tried to also change the validation rules, but even then they are ignored.

I am kind of blind from it, looking into it quite a while, but still nothing.

I'd be grateful for every help here.

Thank you

EDIT:

def create
  @rate_index = RateIndex.new(rate_index_params)
    respond_to do |format|
      if @rate_index.save
        format.html { redirect_to '/rate_indices/new', notice: 'Rate was successfully added.' }
        format.json { render action: 'show', status: :created, location: @rate_index }
      else
        format.html { render action: 'new' }
        format.json { render json: @rate_index.errors, status: :unprocessable_entity }
      end
    end
end

Answer 1

you need to call valid? on your object first to trigger the validation

@rate_index.valid?
@rate_index.errors