Try using params instead of variables. The variables lose scope when changing between views/controllers and once that happens, the value becomes nil. Instead of @show_new_expanse_page = true try params['new_expense_page'] = true
and the value will persist until used. the test for this would be changed from <%= link_to 'New Expense', '/expenses/new' if @show_new_expense_page %> to <%= link_to 'New Expense', '/expenses/new' if params['show_new_expense_page'] %> Good luck Bob On Apr 20, 1:11 pm, Colin Law <[email protected]> wrote: > On 20 April 2010 16:03, RichardOnRails > > > > <[email protected]> wrote: > > Hi Colin, > > >>> The following in app\views\vendors\show.html.erb works perfectly > >>> <%= link_to 'New Expense', '/expenses/new' %> > > >>> I have the following in app\controllers\vendors_controller.rb > >>> class VendorsController < ApplicationController > >>> @show_new_expense_page = true > >>> [snip[ > > >>> I now have in app\views\vendors\show.html.erb > >>> <%= link_to 'New Expense', '/expenses/new' if @show_new_expense_page %> > >>> The foregoing link fails to be displayed > > >> I guess in this case that @showExpenseNew is not actually true as you > >> think it is. > > You are so right!! It is nil > > >> look athttp://guides.rubyonrails.org/ > > Excellent guidance; it's excellent > > >> My favorite is to use ruby-debug > > I did that. It took me days to get working. I won't bore you with my > > travails. But knew I needed to be able to debug but I didn't want to > > detour from getting version 1 of my app completed. But your > > suggestion persuaded me otherwise. > > > My goal is to have a variable that is persistent and which: > > 1. Is defined somewhere and initialized to false > > You don't need to define it and set it to false, the code > if variable > is ok to use if variable is not defined - that is the same as false. > So you only need to set it to true where you want it true. > > > 2. Is set to true in app\views\expenses\new.html.erb when the <%= > > link_to 'New Vendor' ... is clicked > > Sounds good > > > 3. Is referenced in app\views\vendors\show.html.erb as a condition for > > whether to display some link > > Also sounds good > > > > > My current guess is to use a session variable, which I've got a lot > > of hope for. If that doesn't work, I'll start a new thread. > > There should not be any need for a session variable, just set it in > the controller and test it in the view. > > > > > Best wishes, > > Richard > > > BTW, some of my failures are: > > My first attempt to see whether a shared value would work with > > @show_new_expense_page = true in app\controllers > > \vendors_controller.rb > > failed in app\views\vendors\show.html.erb > > because @show_new_expense_page was nil, > > Why is it nil if you are setting in in the controller? Are you sure > it is executing that line in the controller. Break there with > ruby-debug and check. > > > which ruby_debug demonstated for me, thanks to you. > > > My second attempt changed to a class variable @show_new_expense_page > > in both places, which resulted in a syntax error. > > Your first attempt just above is already a class variable, as it > starts with @ so I don't follow you here. > > > > > My third attemp was to initialize @show_new_expense_page in > > app\controllers\application_controller.rb > > No need for it in application_controller, only things that all > controllers need go here. > > Colin > > > which led to NameError in Vendors#show > > uninitialized class variable @@show_new_expense_page in > > ActionView::Base::CompiledTemplates > > -- > 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 > athttp://groups.google.com/group/rubyonrails-talk?hl=en. -- 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.
