Question

I have checked some tutorials but I got confused by the parameters in this method

collection_select (object, attribute, collection, value_method, text_method, options = {}, html_options ={})

I have a map model includes: :area, :system, :file

and I want to read :area from database to a drop down list, and let user choose one

I already did @map = Map.all in the view

what the method should be?

especially the parameter “attribute”. In a lot tutorials, people put “id” here. But I don’t know what “id” is, and in my situation I don’t need any other value, just the “area”.

Answer 1

Im not exactly sure what you are asking here but if you are trying to make a dropdown selection for use in an html form will this example help you at all?

<% nations = {'United States of America' => 'USA', 'Canada' => 'Canada', 'Mexico' => 'Mexico', 'United Kingdom'=> 'UK'} %>
<% list = nations.sort %>
<%= f.select :country, list, %>

Here nations is a hash of countries then list becomes the sorted copy of that hash. An html dropdown is then created as a part of the form “f”. “:country” is the part of the model that the data is connected to while list is the options to populate the dropdown with