nil：NilClass的未定义方法'id'（Controller＃create）

debugcn 发表于 Dev

猫

NameError in CommentsController#create undefined method `id' for nil:NilClass

下一行的错误。我想user_id在当前时间授权的字段（注释表）id用户中保存：

update_column(:user_id, user.id)

模型

class Comment < ActiveRecord::Base
  belongs_to :user
  has_many :likes

  after_save :update_comments
  def update_comments
    update_column(:user_id, user.id)
    true
  end
end

class User < ActiveRecord::Base
  validates :name, presence: true, uniqueness: true
  has_secure_password
  has_many :comments
end

Comments_controller.rb

def create
    @user = User.all
    @comment = Comment.all
    @comment = Comment.new(comment_params)

    respond_to do |format|
      if @comment.save
        format.html { redirect_to @comment, notice: 'Comment was successfully created.' }
        format.json { render action: 'show', status: :created, location: @comment }
      else
        format.html { render action: 'new' }
        format.json { render json: @comment.errors, status: :unprocessable_entity }
      end
    end
  end

**查看/ _表格**

<%= simple_form_for(@comment) do |f| %>
  <%= f.error_notification %>

  <div class="form-inputs">
    <%= f.input :text %>
  </div>

  <div class="form-actions">
    <%= f.button :submit %>
  </div>
<% end %>

会话数/新

<%= form_tag do %>
          <div class="as"><% if flash[:alert] %>
                <p id="notice"><%= flash[:alert] %></p>
            <% end %></div>
          <br><br>
          <fieldset>

            <legend></legend>
            <dl>
              <dt><label for="email">Log in:</label></dt>
              <dd><%= text_field_tag :name, params[:name], class: "user" %></dd>
            </dl>
            <dl>
              <dt><label for="password">Password:</label></dt>
              <dd><%= password_field_tag :password, params[:password], class: "password" %></dd>
            </dl>
          </fieldset>


          <fieldset class="action">
            <input type="submit" name="submit" id="submit" value="Enter" />
          </fieldset>
      <% end %>

格罗弗海滩

尝试使用

def create
@user = User.all
@comment = Comment.all
@comment = @current_user.comments.new(comment_params)

respond_to do |format|
  if @comment.save
    format.html { redirect_to @comment, notice: 'Comment was successfully created.' }
    format.json { render action: 'show', status: :created, location: @comment }
  else
    format.html { render action: 'new' }
    format.json { render json: @comment.errors, status: :unprocessable_entity }
  end
end

结尾

然后，您无需显式分配user_id给comment after_create。使用关联，它将自动为注释分配user_id。

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