English 中文(简体)
how to use an array in form_for?
原标题:

I ve got a user model which contains a field called, lets say, text1. In the users/new form I want to have 4 individual text boxes for this text1. In my model I will take values from these boxes and concatenate them together as comma separated values and store them in the DB. To give you an understanding, this is what I want.

<input type="text" name="user[text1][]" />
<input type="text" name="user[text1][]" />
<input type="text" name="user[text1][]" />
<input type="text" name="user[text1][]" />

How do I get this using form_for helper method? For now please don t worry yourself about the accessor method in the model, that is all taken care of. Thanks a ton.

最佳回答

Add few virtual attributes to your User model

class User < ActiveRecord::Base
  attr_accessor :text1_part1  
  attr_accessor :text1_part2  
  attr_accessor :text1_part3  
  attr_accessor :text1_part4

  def before_validation
      self.text1 = "#{self.text1_part1}#{self.text1_part2}#{self.text1_part3}#{self.text1_part4}"
  end
  # make sure you fill the correct values for
  # the text parts for an existing record.
  # This can be done by implementing `after_find` or overriding
  # `text1=`.
end  

In your view code use the new attributes instead of text1

<% form_for(:user) do |f| %>
   #some code
   <%= f.text_field :text1_part1>
   <%= f.text_field :text1_part2>
   <%= f.text_field :text1_part3>
   <%= f.text_field :text1_part4>
   #some code
   <%= f.submit "Save">
<% end %>
问题回答

The previous answer gives a solution, so I am just providing some background as to why what you are asking for does not work they way you might hope.

You can indeed create a form with multiple input fields of the same name, and that data will be posted. However, when rails receives the post it automatically parameterizes the post data and/or url parameters. It essentially splits on the & and assigns the key/value pairs to the params hash. The outcome of this is that params[:user][:text1] (from your example) will have the value of the last instance of the user[text1] it encountered, since it is simply a value assignment to an existing key. You might want to dig into ActiveRecord multiparameter assignments to get an idea of how datetime attributes work, since they are similar to your use-case.

I am working on something similar and it sounds like maybe serialization is what you are looking for. Unfortunately I don t have my issues solved yet, so I can t provide anything more concrete.





相关问题
rails collection_select vs. select

collection_select and select Rails helpers: Which one should I use? I can t see a difference in both ways. Both helpers take a collection and generates options tags inside a select tag. Is there a ...

SSL slowness in EC2

We ve deployed our rails app to EC2. In our setup, we have two proxies on small instances behind round-robin DNS. These run nginx load balancers for a dynamically growing and shrinking farm of web ...

Auth-code with A-Za-z0-9 to use in an URL parameter

As part of a web application I need an auth-code to pass as a URL parameter. I am currently using (in Rails) : Digest::SHA1.hexdigest((object_id + rand(255)).to_s) Which provides long strings like : ...

RubyCAS-Client question: Rails

I ve installed RubyCAS-Client version 2.1.0 as a plugin within a rails app. It s working, but I d like to remove the ?ticket= in the url. Is this possible?

activerecord has_many :through find with one sql call

I have a these 3 models: class User < ActiveRecord::Base has_many :permissions, :dependent => :destroy has_many :roles, :through => :permissions end class Permission < ActiveRecord::...

Ordering a hash to xml: Rails

I m building an xml document from a hash. The xml attributes need to be in order. How can this be accomplished? hash.to_xml

Text Editor for Ruby-on-Rails

guys which text editor is good for Rubyonrails? i m using Windows and i was using E-Texteditor but its not free n its expired now can anyone plese tell me any free texteditor? n which one is best an ...

How to get SQL queries for each user where env is production

I’m developing an application dedicated to generate statistical reports, I would like that user after saving their stat report they save sql queries too. To do that I wrote the following module: ...

热门标签