如何在字段旁边显示错误消息

Question

我有一个带有输入字段/标签等的表单。如何让错误消息显示在字段旁边？而不是在顶部聚集在一起？

我正在使用 devise，rails 3

我在表单顶部有这个：

 = form_for(resource, :as => resource_name, :url => registration_path(resource_name)) do |f|
- if resource.errors.any?
  #errorExplanation
    %h2
      = pluralize(resource.errors.count, "error")
      prevented this user from being saved:
    %ul
      - resource.errors.full_messages.each do |msg|
        %li
          = msg

Answer 1

如果您想将错误消息放在文本字段的正下方，您可以这样做

.row.spacer20top
  .col-sm-6.form-group
    = f.label :first_name, "*Your First Name:"
    = f.text_field :first_name, :required => true, class: "form-control"
    = f.error_message_for(:first_name)

---

What is error_message_for？
-->嗯，这是一个漂亮的技巧，可以做一些很酷的事情

# Author Shiva Bhusal
# Aug 2016
# in config/initializers/modify_rails_form_builder.rb
# This will add a new method in the `f` object available in Rails forms
class ActionView::Helpers::FormBuilder
  def error_message_for(field_name)
    if self.object.errors[field_name].present?
      model_name              = self.object.class.name.downcase
      id_of_element           = "error_#{model_name}_#{field_name}"
      target_elem_id          = "#{model_name}_#{field_name}"
      class_name              = 'signup-error alert alert-danger'
      error_declaration_class = 'has-signup-error'

      "<div id=\"#{id_of_element}\" for=\"#{target_elem_id}\" class=\"#{class_name}\">"\
      "#{self.object.errors[field_name].join(', ')}"\
      "</div>"\
      "<!-- Later JavaScript to add class to the parent element -->"\
      "<script>"\
          "document.onreadystatechange = function(){"\
            "$('##{id_of_element}').parent()"\
            ".addClass('#{error_declaration_class}');"\
          "}"\
      "</script>".html_safe
    end
  rescue
    nil
  end
end

---

结果

错误后生成的标记

<div id="error_user_first_name" for="user_first_name" class="signup-error alert alert-danger">This field is required.</div>
<script>document.onreadystatechange = function(){$('#error_user_first_name').parent().addClass('has-signup-error');}</script>

对应的 SCSS

  .has-signup-error{
    .signup-error{
      background: transparent;
      color: $brand-danger;
      border: none;
    }

    input, select{
      background-color: $bg-danger;
      border-color: $brand-danger;
      color: $gray-base;
      font-weight: 500;
    }

    &.checkbox{
      label{
        &:before{
          background-color: $bg-danger;
          border-color: $brand-danger;
        }
      }
    }

注意：此处使用引导变量
并且，不要忘记立即重新启动服务器以及对配置目录中的文件进行任何修改后。

Answer 2

您可以使用 error_message_on
http://apidock.com/rails/ActionView/Helpers/ActiveRecordHelper/error_message_on

更新：

form.error_messages 已从 Rails 中删除，现在可以作为插件使用。请使用 rails plugin install git://github.com/rails/dynamic_form.git 安装它。

Answer 3

如果有人正在寻找一种方法来显示 Rails 6 中特定字段的错误消息：

a = Post.new
a.save # => false
a.errors.full_messages_for(:title)
["Title can't be blank"]

a.errors.full_messages_for(:title).join(', ')
"Title can't be blank, Title too short"

Answer 4

您可以使用这个

- if @resource.errors[:field_name]
  ...

也有用的链接：

http://guides.rubyonrails.org/active_record_validations.html#working-with-validation -错误

Answer 5

只需在初始化程序文件夹中创建一个文件即可。

config/initializers/inline_errors.rb

将此代码放入其中：

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  unless html_tag =~ /^<label/
    %{<div class="has-error">#{html_tag}<span class="help-block">#{instance.error_message.first}</span></div>}.html_safe
  else
    %{#{html_tag}}.html_safe
  end
end

PD：抱歉我的英语。