Why is my rails simple validation not working

I have a very basic rails app. I am playing around with validation.

Controller

class PagesController < ApplicationController
  def new
    @user = User.new
  end
  def edit开发者_如何学运维
    @user = User.new(:state => params[:state], :country => params[:country])
    @user.save
  end
end

Model

class User < ActiveRecord::Base
    validates_presence_of :country
    validates_presence_of :state
end

Views/pages/edit.html.erb

<% form_for :user, @user, :url => { :action => "edit" } do |f| %>
  <%= f.text_field :country %>
  <%= f.text_field :state %>
  <%= submit_tag 'Create' %>
<% end %>

All I want to do is click Create when I have not entered anything and then have a validation come up and list the required fields. I've read some tutorials and they make it so simple. Why can't I get this to work? what am i doing wrong? When i create a scaffold then it works ok but that generates a scaffold.css in public/stylesheets. W/out scaffold right now i have no stylesheet in the public folder.

---

you're sending the form to the "edit" action, which doesn't do any processing. You need it to go to the "create" action, which should look something like this:

def create
  @user = User.new(params[:user])

  if @user.save
    flash[:notice] = 'Your user was successfully created.'
    redirect_to users_path
  else
    render :action => 'edit'
  end
end

Your form_for line can be short and sweet. Also, you need to call error_messages to get the auto-generated list of errors:

<% form_for @user do |f| %>
  <%= f.error_messages %>
  ...other fields go here...
<% end %>

---

See Rails conditional validation: if: doesn't working

It seems like you think validates ... if: works differently as it actually does. This line

validates :to_id, presence: true, if: :from_different_to?

translates to validate that the to_id is present if the from_different_to method returns true. When from_different_to evaluates to false then do not validate.