Error messages from model in Rails 3.2 -

currently app includes following code to display error messages on view model.rb not updated code error_messages_for deprecated in rails 3. can please suggest me how same in rails 3?? want logic in model.rb file , there should able display error msgs on view

excel_file.rb(model.rb)

#jus sample function def show_error(test_file)     if test_file == 'upload test case'       errors[:base] << "please upload excel sheet testsuite config sheet , testcases"      elsif test_file == 'upload test data'       errors[:base] << "please upload excel sheet test data"      end   end 

sampleview.html.erb

 #some code..    <span class='error'><%= error_messages_for (@excel_file) %></span>      #some code.. 

application_helper.rb

def error_messages_for(*objects)   html = ""   objects = objects.map {|o| o.is_a?(string) ? instance_variable_get("@#{o}") : o}.compact   errors = objects.map {|o| o.errors.full_messages}.flatten   if errors.any?     html << "<div id='errorexplanation'><ul>\n"     errors.each |error|       html << "<li>#{h error}</li>\n"     end     html << "</ul></div>\n"   end   html.html_safe end 

you use https://github.com/rails/dynamic_form.

it provides functionality want.

update

you right, not in accordance rails 3.

you should this:

create shared partial

/app/views/shared/_error_messages.html.erb

<% if target.errors.any? %>   <div id="errorexplanation">     <h2><%= pluralize(target.errors.count, "error") %> prohibited record being saved:</h2>     <ul>     <% target.errors.full_messages.each |msg| %>       <li><%= msg %></li>     <% end %>     </ul>   </div>   <% end %> 

and call this:

<%= render "shared/error_messages", :target => @excel_file %> 

so why methods error_messages_for , f.error_messages removed? ryan bates says following:

the reason methods have been removed display of error messages needs customized , doing through old methods little bit cumbersome , not flexible having error message html inline have now. having html hand in views means can change display of error messages like.

source: http://asciicasts.com/episodes/211-validations-in-rails-3

update 2

this works custom validations same way

validate :show_error  def show_error   if test_file == 'upload test case'     errors[:base] << "please upload excel sheet testsuite config sheet , testcases"    elsif test_file == 'upload test data'     errors[:base] << "please upload excel sheet test data"    end end