Question

新手在这里...在轨道上学习ryby大约4个星期，第一个项目，找不到什么错误，会很感激一些帮助。

_form（第2行中的错误）：

<%= simple_form_for @workshop, :html => { :multipart => true } do |f| %>
 <%= select_tag(:category_id, options_for_select(@categories), :prompt => "Escolher Categoria") %>

 <%= f.file_field :workshop_img %>
 <%= f.input :title, label: "Nome do Workshop" %>
 <%= f.input :description, label: "Descrição" %>
 <%= f.input :author, label: "Formador" %>
 <%= f.button :submit %>

workshops_controller：

class WorkshopsController < ApplicationController
before_action :find_workshop, only: [:show, :edit, :update, :destroy]

def index
if params[:category].blank?
    @workshops = Workshop.all.order("created_at DESC")  
else
  @category_id = Category.find_by(name: params[:category]).id
  @workshops = Workshop.where(:category_id =>   @category_id).order("created_at DESC")
end  
end

def show    
end 

def new
@workshop = current_user.workshops.build
@categories = Category.all.map{ |c| [c.name, c.id] }
end


def create
  @workshop = current_user.workshops.build(workshop_params)
  @workshop.category_id = params[:category_id ]

  if @workshop.save
    redirect_to root_path
  else
    render 'new'
  end     
  end

def edit
  @categories = Category.all.map{ |c| [c.name, c.id] }
end

def update
  @workshop.category_id = params[:category_id]
  if @workshop.update(workshop_params)
    redirect_to workshop_path(@workshop)
  else
    render 'edit'
  end       
end

def destroy
  @workshop.destroy
  redirect_to root_path 
end


private
  def workshop_params
    params.require(:workshop).permit(:title, :description, :author, :category_id, :workshop_img)
  end

def find_workshop 
  @workshop = Workshop.find(params[:id])    
end    
end

类别模型

has_many :workshops
end

用户模型

has_many :workshops

车间模型

belongs_to :user
belongs_to :category

 has_attached_file :workshop_img, styles: { workshop_index: "250x350>",    workshop_show: "325x475>" }, default_url: "/images/:style/missing.png"

validates_attachment_content_type :workshop_img, content_type: /\Aimage\/.*\z/   
end

schema.rb

create_table "categories", force: :cascade do |t|
t.string   "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end

create_table "users", force: :cascade do |t|
  t.string   "email",                  default: "", null: false
  t.string   "encrypted_password",     default: "", null: false
  t.string   "reset_password_token"
  t.datetime "reset_password_sent_at"
  t.datetime "remember_created_at"
  t.integer  "sign_in_count",          default: 0,  null: false
  t.datetime "current_sign_in_at"
  t.datetime "last_sign_in_at"
  t.string   "current_sign_in_ip"
  t.string   "last_sign_in_ip"
  t.datetime "created_at",                          null: false
  t.datetime "updated_at",                          null: false
  t.index ["email"], name: "index_users_on_email", unique: true
  t.index ["reset_password_token"], name:     "index_users_on_reset_password_token", unique: true
end

create_table "workshops", force: :cascade do |t|
  t.string   "title"
  t.string   "author"
  t.text     "description"
  t.datetime "created_at",                null: false
  t.datetime "updated_at",                null: false
  t.integer  "user_id"
  t.integer  "category_id"
  t.string   "workshop_img_file_name"
  t.string   "workshop_img_content_type"
  t.integer  "workshop_img_file_size"
  t.datetime "workshop_img_updated_at"
  end

end

Answer 1

我们可以获得有关正在生成的错误的一些信息吗？ rails错误消息往往比其他语言更有用。如果你说表格的第2行有错误，我可以看到，如果你可以复制并粘贴错误的输出，那么它应该突出显示问题。

Answer 2

我明白了！在您的create操作中，您呈现了新的＆＃39;查看（如果保存失败），需要@categories。但是你不能在创建动作中创建它们。有nil来自。

Workshops中的NoMethodError #create

2 个答案: