如何在collection_select类型字段上添加必需的true

Question

我已经尝试在collection_select字段上添加required => true和：prompt =>“select ...”，但每次出现语法错误。如何解决下面这个错误。

.field
  = f.label "Receiver"
  = f.collection_select(:receiver_admin_id, 
        Admin.agent_and_admin(current_admin.id, current_admin.parent_master_agent_id), 
        :id, 
        :agent_name, 
        :prompt => 'Select receiver', 
        {multiple: true}), 
      :required => true

  = f.collection_select(:receiver_admin_id, 
        Admin.agent_and_admin(current_admin.id, current_admin.parent_master_agent_id), 
        :id, 
        :agent_name, 
        :prompt => 'Select receiver', 
        {multiple: true, required: true})

  = f.collection_select(:receiver_admin_id, 
        Admin.agent_and_admin(current_admin.id, current_admin.parent_master_agent_id), 
        :id, 
        :agent_name, 
        :prompt => 'Select receiver',
        {}, 
        {multiple: true}), 
      :required => true

  = f.collection_select :receiver_admin_id, 
        Admin.agent_and_admin(current_admin.id, current_admin.parent_master_agent_id), 
        :id, 
        :agent_name, 
        :prompt => 'Select receiver', 
        {multiple: true}, 
        :required => true

Answer 1

请试试这个：

  = f.collection_select :receiver_admin_id, Admin.agent_and_admin(current_admin.id, current_admin.parent_master_agent_id), :id, :agent_name, {prompt: 'Select receiver'}, {multiple: true, required: true}

Answer 2

几乎每次都很接近:)从文档in the rails guide你有：

collection_select(object, method, collection, value_method, text_method, options = {}, html_options = {})

使用表单助手（f.）意味着对象（第一个参数）被处理，所以你留下：

method, collection, value_method, text_method, options, html_options

多个和必需都需要在html_options中：

= f.collection_select(:receiver_admin_id, Admin.agent_and_admin(current_admin.id, current_admin.parent_master_agent_id), :id, :agent_name, { :prompt => 'Select receiver' }, multiple: true, :required => true)