Hi Colin, I had to work on adding authenticated users to my app, so I had to back-burner the conditional-link issue. I nevertheless would like to keep trying to learn how to do this. Maybe CSS is the way to make the link switch between visible or not depending on context. (Just my inspiration at the moment.)
Also, you mentioned that I needed have my switch initialized to false, because nil will result in the same thing, so I just commented it out in VendorController. Seems to clear up one problem. > Your first attempt just above is already a class variable, as it > starts with @ so I don't follow you here. I think @xxx defines an instance variables while @@xxx defines a class variable in Ruby. That's what my Ruby books tell me, as does http://www.rubyist.net/~slagell/ruby/instancevars.html. It's nice that we got a couple of other respondents. Maybe we'll get this resolved shortly. Best wishes, Richard 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.
