如何包含“请选择...” （默认/提示）在分组下拉列表中？

发布于 2024-12-25 07:39:08 字数 291 浏览 2 评论 0原文

我用于下拉列表的代码是这样的：

<%= f.select :post_type_id, option_groups_from_collection_for_select(@categories, :post_types, :name, :id, :name) %>

它将选项整齐地划分为选项组。

但是如何修改代码以包含“请选择...”的提示（或默认值）？

分组下拉菜单似乎很难做到。（rails 文档似乎建议使用哈希，但我尝试了几种替代方法但没有成功。）

原文

The code I am using for the dropdown list is this:

<%= f.select :post_type_id, option_groups_from_collection_for_select(@categories, :post_types, :name, :id, :name) %>

It neatly divides the options into optgroups.

But how do I modify the code to include a prompt (or a default value) of "Please select..." ?

It seems hard to do with grouped dropdowns.
(The rails docs seem to suggest using a hash, but I've tried several alternatives without success.)

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花间憩 2025-01-01 07:39:08

啊，在我发布问题后，我发现答案就在 select 的文档中，而不是在我一直在寻找的 option_groups_from_collection_for_select 文档中。

答案是：

<%= f.select :post_type_id, option_groups_from_collection_for_select(@categories, :post_types, :name, :id, :name), :include_blank => "Please select..." %>

Bah, right after I posted the question I found the answer was in the docs for select, and not under option_groups_from_collection_for_selectdocs where I had been looking.

The answer is:

<%= f.select :post_type_id, option_groups_from_collection_for_select(@categories, :post_types, :name, :id, :name), :include_blank => "Please select..." %>

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