ruby-on-rails - 使用 Rails 创建操作的多选

Question

我有一个 Collection_select，其中 Multiple 设置为 true

 #views/courses/new
<%=collection_select(:course, :department_id, Department.all, :id, :name, {},
:multiple =>true,:size => 8,:class=> "text")%>

在我的模型中

#deparment Model
has_many :courses
#Course Model
belongs_to :deparment

我想要一种情况，如果一门课程从多选列表中选择了多个部门，则此详细信息将保存在课程表中。My Current Implementation 仅保存课程的第一个选定部门，并丢弃其余部门。请我如何实现这一点。

def create
@course = Course.new(params[:course] || [])
if @course.save
  redirect_to courses_path, :notice => "Course Created Successfully"
else
  redirect_to new_course_path
  flash[:alert] = "Error Creating Course"
end
end

谢谢你

Answer 1

您将需要两个对象的 Has And Belongs To Many (HABTM) 关联。看看这个：

http://guides.rubyonrails.org/association_basics.html#the-has_and_belongs_to_many-association

Answer 2

首先..你应该有这样的联想。

部门.rb

has_and_belongs_to_many :courses

课程.rb

has_and_belongs_to_many :departments

而且你可以有这样的观点/课程/新的。

<%=text_field_tag :course_name)%>
<%=select_tag(:departments, options_from_collection_for_select(Department.all, :id, :name),:multiple =>true,:size => 8,:class=> "text")%>

和创建动作将是这样的。

def create
  @course = Course.new(params[:course_name] || [])
  if @course.save
    params[:departments].split(',').each do |id|
      @course.departments << Department.find(id)
    end
    redirect_to courses_path, :notice => "Course Created Successfully"
  else
    redirect_to new_course_path
    flash[:alert] = "Error Creating Course"
  end
end

加入表的迁移

class CreateCoursesDepartments < ActiveRecord::Migration
  def change
    create_table :courses_departments do |t|
      t.integer :course_id
      t.integer :department_id

    end
  end
end