collection_select 类型字段上的必填字段

Question

我有一个带有简单文本字段的表单，我需要填写该表单：

<%= f.text_field :email, :required => true %>

下一个字段是一个 collection_select 类型，我想强制用户选择一个选项。我试过了：

<%= f.collection_select(:list_ids, List.where(user_id: current_user), :id, :name, {}, {multiple: true}), :required => true %>

这给了我错误：

syntax error, unexpected ',', expecting ')' ..., :name, {}, {multiple: true}), :required => true );@output_... ... ^

如果没有:required => true 选项，代码可以正常工作。在这种情况下，如何强制用户进行选择？谢谢

Answer 1

尝试更改此设置

<%= f.collection_select(:list_ids, List.where(user_id: current_user), :id, :name, {}, {multiple: true}), :required => true %>

到这里

<%= f.collection_select :list_ids, List.where(user_id: current_user), :id, :name, {}, {multiple: true, required: true} %>

Answer 2

试试这个

<%= f.collection_select(:list_ids, List.where(user_id: current_user), :id, :name, {}, {multiple: true, required: true}) %>

解释：

根据 Rails 文档，collection_select 函数的语法如下所示：

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

根据语法选项和 html_options 是哈希，因此您需要将它们括在大括号中。

参考 - http://apidock.com/rails/ActionView/Helpers/FormOptionsHelper/collection_select

Credit

Answer 3

<%= form.collection_select :msr_cd, 
    @msrs, :msr_cd, :msr_cd,
      {multiple: false, required: true},
      data: { placeholder: "Select Measure" }, 
      class: "form-control col-sm-12 chosen-select"  
%>

Note:
    @msrs from the controller
    :msr_cd - option value`enter code here`
    :msr_cd - option text

We can pass the chosen select like above