Problems with error_messages_for

rubyonrails-talk
1

I can't get my error messages to display. Maybe I don't yet understand page life cycle or something? ROR is an elegant solution but the transition from ASP.net has been painful to say the least. Code below any help would be greatly appreciated.

<% form_for :inventory_line_item, :url => { :action => :create_inventory_item, :id =>@product } do |form| %> <%= error_messages_for 'inventory_line_item' %> <ol>   <li>     <label for="inventory_line_item_quantity">Quantity</label>     <%= form.text_field 'quantity' %>   </li>

Model

class InventoryLineItem < ActiveRecord::Base   belongs_to :products

validates_presence_of :date_added, :added_by, :quantity, :unit_case, :case_price   validates_numericality_of :case_price, :message=>"Price must be a valid decimal number"

  protected   def validate     errors.add(:case_price, "should be at lease 0.01") if case_price.nil? || case_price < 0.01   end

end

controller

  def inventory       @product = Product.find(params[:id])      @inventory_line_item = InventoryLineItem.new   end

  def create_inventory_item    member = Member.find(session[:member_id])

    @product = Product.find(params[:id])    line_item = InventoryLineItem.new(params[:inventory_line_item])    line_item.date_added = Date.today    line_item.added_by = member.name    @product.inventory_line_items << line_item

    if @product.save       flash[:notice] = 'Inventory successfully added'       redirect_to :action => 'inventory', :id => @product     end       redirect_to :action => 'inventory', :id => @product   end

2

I can’t get my error messages to display. Maybe I don’t yet understand page life cycle or something? ROR is an elegant solution but the transition from ASP.net has been painful to say the least. Code below

any help would be greatly appreciated.

<% form_for :inventory_line_item, :url => { :action => :create_inventory_item, :id =>@product } do |form| %> <%= error_messages_for ‘inventory_line_item’ %>

This line requires that you have the instance variable @inventory_line_item set and containing the object that you are interested in.

  1. Quantity <%= form.text_field 'quantity' %>

    2. Model

    class InventoryLineItem < ActiveRecord::Base belongs_to :products

    validates_presence_of :date_added, :added_by, :quantity, :unit_case, :case_price

        validates_numericality_of :case_price,  :message=>"Price must be a

    valid decimal number"

        protected
    def validate
            errors.add(:case_price,

    “should be at lease 0.01”) if case_price.nil? || case_price < 0.01 end

    end

    controller

        def inventory
        @product = Product.find(params[:id])

    @inventory_line_item = InventoryLineItem.new end

        def create_inventory_item
     member = Member.find(session[:member_id])

@product    = Product.find(params[:id])

    line_item = InventoryLineItem.new(params[:inventory_line_item]) line_item.date_added = Date.today

    line_item.added_by
    = member.name @product.inventory_line_items << line_item

    if @product.save
  flash[:notice] = 'Inventory successfully added'
  redirect_to :action => 'inventory', :id => @product

end
  redirect_to :action => 'inventory', :id => @product
    end

line_item in the create action should be

@inventory_line_item

This should then see it

3

I follow your logic, if I am using the instance variable it will not get passed back to the page.

I made the following change but am still not getting any error messaging? Could it be because I am using @product.save with <%= error_messages_for 'inventory_line_item' %> or could it be that I am instantiating and new inventory_line_item in inventory? Maybe the errors are not bubbling up or something. I am confused for sure on this one.

  #inventory controls   def inventory       @product = Product.find(params[:id])      @inventory_line_item = InventoryLineItem.new   end

  def create_inventory_item    member = Member.find(session[:member_id])

    @product = Product.find(params[:id])    @inventory_line_item = InventoryLineItem.new(params[:inventory_line_item])    @inventory_line_item.date_added = Date.today    @inventory_line_item.added_by = member.name    @product.inventory_line_items << @inventory_line_item       if @product.save         flash[:notice] = 'Inventory successfully added'       end       redirect_to :action => 'inventory', :id => @product   end

4

I follow your logic, if I am using the instance variable it will not get passed back to the page.

That's not quite it. The error_messages_for method looks for an instance variable with the name given in the argument.

In the docs

Returns a string with a div containing all of the error messages for the objects located as instance variables by the names given. If more than one object is specified, the errors for the objects are displayed in the order that the object names are provided.

I made the following change but am still not getting any error messaging? Could it be because I am using @product.save with <%= error_messages_for 'inventory_line_item' %> or could it be that I am instantiating and new inventory_line_item in inventory? Maybe the errors are not bubbling up or something. I am confused for sure on this one.

I believe the problem is that you are not saving @inventory_line_item or at least calling the validation, and it is not saving as part of the @product.save.

You will need to at least run the valid? method on the @inventory_line_item or make sure that an attempt has been made to save it.

Hope that helps.

5

Thanks Daniel,

Below is the code that fixed this issue. I had to check the valid method first like you said and the key to making the validation display was using the render action: => to redisplay the page like this. When you redirect_to do you loose the state of the error_message_for? I will need to read up on that. Thanks againf for your help.

     @inventory_line_item.added_by = member.name       if @inventory_line_item.valid?        @product.inventory_line_items << @inventory_line_item         if @product.save            flash[:notice] = 'Inventory successfully added'          redirect_to :action => 'list'          end     else       render :action => :inventory     end