Ruby-on-rails Rails 中的下拉框
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Drop down box in Rails
提问by alamodey
How do I use Rails to create a drop-down selection box? Say if I have done the query:
如何使用 Rails 创建下拉选择框？说我是否已经完成了查询：
@roles = Role.all
Then how do I display a box with all the @roles.name's ?
那么如何显示一个包含所有@roles.name 的框？
EDIT:After implementing the dropdown box. How do I make it respond to selections? Should I make a form?
编辑：实现下拉框后。我如何让它响应选择？我应该制作表格吗？
回答by David Burrows
use the collection_select helper http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#M001593
使用 collection_select 助手 http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#M001593
This will allow you to write something like:
这将允许您编写如下内容：
collection_select(:user, :role_id, @roles, :id, :role_title, {:prompt => true})
And get
并得到
<select name="user[role_id]">
<option value="">Please select</option>
<option value="1" selected="selected">Administrator</option>
<option value="2">User</option>
<option value="3">Editor</option>
</select>
回答by erik
This will create a drop down that displays the role name in the drop down, but uses the role_id as the value passed in the form.
这将创建一个下拉列表，在下拉列表中显示角色名称，但使用 role_id 作为表单中传递的值。
select("person", "role_id", @roles.collect {|r| [ r.name, r.id ] }, { :include_blank => true })
回答by Jamie Rumbelow
The form helper has a group of methods specifically written to create dropdown select boxes. Usually you'll use the select_tagmethod to create dropdown boxes, but in your case you can use collection_select, which takes an ActiveRecord model and automatically populates the form from that. In your view:
表单助手有一组专门用于创建下拉选择框的方法。通常，您将使用select_tag方法创建下拉框，但在您的情况下，您可以使用 collection_select，它采用 ActiveRecord 模型并自动从中填充表单。在您看来：
<%= collection_select @roles %>
Find out more about the Rails form helper here: http://guides.rubyonrails.org/form_helpers.html
在此处了解有关 Rails 表单助手的更多信息：http: //guides.rubyonrails.org/form_helpers.html
回答by V-SHY
Display role name as comboBox showing text (1st pluck argument) and it represents the role id
将角色名称显示为显示文本的组合框（第一个 pluck 参数），它代表角色 ID
Controller
控制器
@roles = Role.pluck(:name, :id)
View
看法
<%= select("role", "role_id", @roles) %>
params[:role][:role_id]passed to controller from view.
params[:role][:role_id]从视图传递给控制器。
