Pics＃show中的NoMethodError

Question

如果我访问http：// localhost：3000 / pics / 9或任何帖子，我会收到此错误

Showing c:/Sites/insta/app/views/pics/show.html.haml where line #5 raised:

undefined method `email' for nil:NilClass
Rails.root: c:/Sites/insta

Application Trace | Framework Trace | Full Trace
app/views/pics/show.html.haml:5:in `_app_views_pics_show_html_haml__310592347_80083632'

show.html.haml

%h1= @pic.title
%p= @pic.description
%p
Pic by 
= @pic.user.email

%br

= link_to "Back", root_path
= link_to "Edit", edit_pic_path
= link_to "Delete", pic_path, method: :delete, data: { confirm: "Are you sure?" }

shema.rb

# encoding: UTF-8
# This file is auto-generated from the current state of the database. Instead
# of editing this file, please use the migrations feature of Active Record to
# incrementally modify your database, and then regenerate this schema definition.
#
# Note that this schema.rb definition is the authoritative source for your
# database schema. If you need to create the application database on another
# system, you should be using db:schema:load, not running all the migrations
# from scratch. The latter is a flawed and unsustainable approach (the more migrations
# you'll amass, the slower it'll run and the greater likelihood for issues).
#
# It's strongly recommended that you check this file into your version control system.

ActiveRecord::Schema.define(version: 20160825161502) do

  create_table "pics", force: :cascade do |t|
    t.string   "title"
    t.text     "description"
    t.datetime "created_at",         null: false
    t.datetime "updated_at",         null: false
    t.integer  "user_id"
    t.string   "image_file_name"
    t.string   "image_content_type"
    t.integer  "image_file_size"
    t.datetime "image_updated_at"
  end

  add_index "pics", ["user_id"], name: "index_pics_on_user_id"

  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"
    t.datetime "updated_at"
  end

  add_index "users", ["email"], name: "index_users_on_email", unique: true
  add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true

end

我在寻找解决方案的问题在哪里，但我什么都没找到

Answer 1

问题是您没有与导致该错误的某些Pic相关的user ：

nil：NilClass的未定义方法`email'

您可以通过更改来解决此问题

= @pic.user.email

在show.html.haml第5行中

= @pic.user.try(:email)