Has and Belongs to Many with Multiple Check boxes
So if you are trying to do a multiple select of checkboxes and using habtm in your project, but when you submit the form, only one value was available in your controller. While you try to edit records in database but because of some error you get back to the pre field form and you found that the checkboxes checked by you gone ,then here’s the solution
Model:
class Customer < ActiveRecord::Base
has_and_belongs_to_many :intrests
end
Controller code:
class CustomersController < ApplicationController
def create
if request.post?
@customer=Customer.new(params[:customer])
@customer.save
end
end
def edit
@customer=Customer.find_by_id(params[:id]) if params[:id]
if @customer
if request.post?
if @customer.update_attributes(customer)
flash.now[:message]=”Update successfully “
end
end
else
flash[:message]=”Page requested by you does not exists”
end
end
end
Your View:
<% form_for :customer, do |f| -%>
First Name:
<%= f.text_field :first_name -%>
Last Name:
<%= f.text_field :last_name -%>
<% for intr in total_intrests -%>
<%= check_box_tag "customer[interest_ids][]", "#{intr.id}", interest(intr) -%> # interest is a helper method
<%= "#{intr.name}" -%>
<% end -%>
<% end -%>
helper method
def interest(i)
if @customer
@customer.interests.include?(i)
else
false
end
end
View generate a checkbox for every interest(all_interest=Interest.find(:all)). The name of the input is significant obviously. The trailing “[]” on the name means the end result will be the list of checked ids. This list will be stored on the @params['customer'] hash with the key ‘interest_ids’. When the controller calls @customer.update_attributes(@params[:customer]), it tries to call @customer.key= for each of the keys on @params[:customer]. What’s important to realize is that these keys don’t have to actually be attributes on the Customer model. All that’s important is that there’s a key= method on the model. Model automatically contains a “collection_ids=” method for habtm and has-many associations.
This method will load the objects identified by the ids and call the “interest=(list)” method on the model with the freshly loaded list. This method in turn, will compare the list to the current list of interests and delete/add interests as necessary.
mahesh said
thank u but some what unable to understand clearly,please give me in some datailed one
Satish Chauhan said
hi mahesh
Let me know what point you are not getting ?
and what more detail you want ?
Satish Chauhan
mahesh said
how to display the content of FCK Editor without displaying HTMLtags at users display in ruby on rails
mahesh said
thank u for reply,
i am creating a list of items with every item containing checkboxes.as i have to select some items by clicking checkbox. and when i click on the delete button i have to delete the selected items from the list,and i have to display the same page with remaining list of items.
for that i have declare an array for checkboxes and how i can pass the array to controller to delete the items..
can u please give me the explanation for this …..
Satish Chauhan said
If it is possible, show me your code
i will try to solve your problem
Travis said
Thanks for the code posting. This is exactly what I was looking for!
hiutopor said
Hi
Very interesting information! Thanks!
G’night
neil said
hi there, i’m a having some difficulties to add records in my database.
i tried many ways but cannot succeed.
please help me to give some ideas what’s wrong with my code
by the way, i want to develop a webpage to list all students’ name and tick the checkboxes then click save to save all the students’ attendance.
def createattendance
if params[:id]
@attendance = Teachersubject.find(params[:id])
else
@attendance = Attendance.new
end
if request.post?
@attendance.attributes = params[:attendance][:student_ids]
begin
@attendance.transaction(@attendance) do
@attendance.save!
@attendance.reload unless @attendance.id
raise ActiveRecord::RecordInvalid unless @attendance.valid?
redirect_to :action=>’eattendance’
end
rescue ActiveRecord::RecordInvalid
end
end
end
function checkedAll (id, checked) { var el = document.getElementById(id);
for (var i = 0; i < el.elements.length; i++) {
el.elements[i].checked = checked;
}
}
‘createattendance’%>
Select Subject
<option value=”">
[:day, :month, :year], :start_year => 2007, :end_year => Time.now.year)%>
<input id=”attendance[class1_id]” name=”attendance[class1_id]” size=”1″ type=”varchar” value=”"/>
[]
<INPUT type=”hidden” name=’student[ids][]‘ value=”">
Chris said
Brilliant. And finally got me to use a helper method.