On Sat, Aug 29, 2009 at 1:21 PM, Colin Law <[email protected]> wrote:
> > 2009/8/29 Dhruva Sagar <[email protected]>: > > Hi everyone, > > > > I have recently experienced a strange behavior (strange from my > knowledge) > > in rails. > > > > In my controllers 'new' action, I am creating a few instance variables in > > the following manner : > > > > @controllerModel = ControllerModel.new > > @model1 = Model1.all > > @model2 = Model2.all > > > > in my 'new' view, I am using the @controllerModel to create the form for > new > > and I am using the @model1 & @model2 within the form to populate 2 combo > > boxes in the following manner : > > > > f.select :model1_id, @model1.collect { |m1| [m1.name, m1.id] } > > > > f.select :model2_id, @model2.collect { |m2| [m2.name, m2.id] } > > > > Now everything works fine, the form is generated fine, there are no > errors > > even the form submit works fine when I ensure that all the required > fields > > (ControllerModel validations). > > > > But in the event some of my validations fail and in the controller I do a > > render :action => 'new' I am given an error / exception for @model1 & > > @model2 being nil. I don't understand the reason for the same, I am > looking > > for an explanation for this. > > > > The reason is that the @model1 and @model2 variables are only > available for the initial render of new. They are setup by you in the > controller, used in the view erb file to generate the html which is > sent to the browser, then they are discarded. Therefore when you get > validation failures and wish to show the view again you must set up > the variables again. One solution is to have a private method of the > controller called something like prepare_for_edit_or_new which you > call where appropriate (you will likely have the same problem in edit) > or, the solution I prefer, is to have Model1 and Model2 methods > get_selection_data or similar that return the equivalent of > @model1.collect { |m1| [m1.name, m1.id] } and then call this directly > from the view, thus eliminating the need for the variables. > > Colin Hi Colin, Thank you very much for your input, I understand it now & yes it happens with edit as well. I think helpers is perhaps the best place to put the code for the @model.collect in. Thanks & Regards, Dhruva Sagar. Pablo Picasso<http://www.brainyquote.com/quotes/authors/p/pablo_picasso.html> - "Computers are useless. They can only give you answers." > > > As a work around of course I found that if I add the following to the > view > > it works out fine, but I don't understand the flow fully, I want to know > why > > the above mentioned error occurs. > > > > work around in 'new' view : > > > > if @controllerModel.errors > > @model1 = Model1.all > > @model2 = Model2.all > > end > > > > Thanks & Regards, > > Dhruva Sagar. > > > > > > Stephen Leacock - "I detest life-insurance agents: they always argue > that I > > shall some day die, which is not so." > > > > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
