如何在rails视图上显示错误消息？

Question

我是rails的新手，想在form的领域申请验证。

myviewsnew.html.erb

<%= form_for :simulation, url: simulations_path do |f| %> 

<div class="form-group"> 
    <%= f.label :Row %> 
    <div class="row"> 
    <div class="col-sm-2"> 
     <%= f.text_field :row, class: 'form-control' %> 
    </div> 
    </div> 
</div> 
..... 

Simulation.rb

class Simulation < ActiveRecord::Base 
belongs_to :user 
validates :row, :inclusion => { :in => 1..25, :message => 'The row must be between 1 and 25' } 
end 

simulation_controller.rb

class SimulationsController < ApplicationController 

    def index 
    @simulations = Simulation.all 
    end 

    def new 
    end 

    def create 
    @simulation = Simulation.new(simulation_params) 
    @simulation.save 
    redirect_to @simulation 
    end 

    private 
    def simulation_params 
    params.require(:simulation).permit(:row) 
    end 

我要检查row场的整数范围模型类和如果它不在范围内，则返回错误消息。我可以从上面的代码检查范围，但不能提前返回错误信息

感谢

Answer 1

的 error_messages_for完整语法

更改您的控制器像下面

def new 
    @simulation = Simulation.new 
end 

def create 
    @simulation = Simulation.new(simulation_params) 
    if @simulation.save 
    redirect_to action: 'index' 
    else 
    render 'new' 
    end 
end 

然后在您的新视图中，如果存在错误，您可以像下面那样打印它们。

<%= form_for @simulation, as: :simulation, url: simulations_path do |f| %> 
    <% if @simulation.errors.any? %> 
    <% @simulation.errors.full_messages.each do |message| %> 
     <li><%= message %></li> 
    <% end %> 
    <% end %> 
    <div class="form-group"> 
    <%= f.label :Row %> 
    <div class="row"> 
     <div class="col-sm-2"> 
     <%= f.text_field :row, class: 'form-control' %> 
     </div> 
    </div> 
    </div> 
<% end %> 

Answer 2

你只需要将此代码添加到视图文件（myviewsnew.html.erb）：

<%= error_messages_for :simulation %> 

检查在http://apidock.com/rails/ActionView/Helpers/ActiveRecordHelper/error_messages_for

Answer 3

做到这一点 -

<%= form_for :simulation, url: simulations_path do |f| %> 
    <% if f.object.errors.any? %> 
     <ul> 
     <% if f.object.errors.each do |message| %> 
      <li><%= message %></li> 
     <% end %> 
     </ul> 
    <% end %> 

    .......... 
<% end %>