Dynamically Generate a Selection List in a Rails Template - A Little Partial Pizzazz
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Thepartialneeds thearrayvalues to build theselectlist; these are stored in theteamArrvariable. Rails uses its built-in naming convention forpartials (the underscore requirement) to find the correct content and render it as the response. Let’s look at thepartial_options.rhtml file:
<select id="<%= sptype %>" name="<%= sptype %>">
<% sports.each do |sport| %>
<option><%= sport %></option>
<% end %>
</select>
A little embedded Ruby code gives theselectelement itsidandname. The embedded code then iterates through thearray(passed into thepartialby therender()method) and creates anoptionelement for eacharraymember, as in<option>hockey</option>. Although a little server-side Ruby code was involved, the code did not have to touch the request object or deal with fetching or massaging the return value.
Cleanup Code
The only bit of trickery involved is making sure that the application does not append one newselect list after another inside thedivas the user clicks the button. We want all the existingselects in thatdivto be replaced by any new ones. Therefore, we include a little cleanup code that empties thedivbefore it’s updated with a newselect list:
<%= form_remote_tag(:update => "sel_con",:url => { :action =>
:create_select
},
:position => "top",success => "$('sel_con').innerHTML=''" ) %>
successsequentially precedes thecompletestage, so this code sets thediv’s content to the emptystring before the newselect list appears.
To handle any request failures, such as a downed web server, add this code from a prior hack as aform_remote_tag()parameter:
#$('failure') is Prototype's shortcut for
#document.getElementById('failure')
:failure => "$('failure').innerHTML='Failure;
request status='+request.status"
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 This article is excerpted from hack 58 of the book Ajax Hacks, written by Bruce W. Perry (O'Reilly; ISBN: 0596101694). Check it out today at your favorite bookstore. Buy this book now.
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