Question

我正在编辑Rails 2应用程序。在其中，用户提交包含下拉菜单的表单，该信息在我的数据库中创建记录。当用户去编辑记录时，我想在下拉菜单中显示已保存的“已选择”选项。但是，我一直都会遇到错误。这是我的设置：

查看选择字段

    <% form_for @newsavedmap, :html=>{:id=>'createaMap'} do |f| %>
    <%= f.select :start, options_for_select(@itinerary.locations), {:include_blank => true}, {:id=>"startdrop" } %>

表单助手

    def options_for_select(locations)
  locations.map do |l|
    content_tag "option", l.masterlocation.name, location_option_attributes(l)
  end.join("\n")
end

private

def location_option_attributes(location)
  {
    :value => "#{location.masterlocation.street_address}, #{location.masterlocation.city}, #{location.masterlocation.state}, #{location.masterlocation.zip}",
    :id => location.masterlocation.id,  
    :"data-masterlocation-name" => location.masterlocation.name,
    :"data-masterlocation-id" => location.masterlocation.id,
    :"data-masterlocation-latitude" => location.masterlocation.latitude,
    :"data-masterlocation-longitude" => location.masterlocation.longitude
  }
end

我试过让视图看起来像这样：

    <%= f.select :start, options_for_select(@itinerary.locations, @newsavedmap.start), {:include_blank => true}, {:id=>"startdrop" } %>

但是我得到错误的参数数量（2比1））。也尝试了

    <%= f.select :start, options_for_select(@itinerary.locations), {:selected => @newsavedmap.start, :include_blank => true}, {:id=>"startdrop" } %>

但是当我去编辑已保存的地图时，没有预先选择。我已经尝试过这些链接，并继续罢工。感谢您提供的任何帮助！

Rails select helper - Default selected value, how?，Rails form_for select tag with option selected，Rails select helper - Default selected value, how?

Answer 1

你可以在你的助手

中尝试这样的事情

   def options_for_select(locations, selected=nil)
      locations.map do |l|
        tag_options = location_option_attributes(l)
        if l == selected
         tag_options[:selected] = "selected" 
        end
        content_tag "option", l.masterlocation.name, tag_options
      end.join("\n")
    end

然后调用你之前尝试过的字段。

<%= f.select :start, options_for_select(@itinerary.locations, @newsavedmap.start), {:include_blank => true}, {:id=>"startdrop" } %>

Answer 2

您可以再传递一个参数来选择这样的值：

<%= f.select :start, options_for_select(@itinerary.locations), :selected => @newsavedmap.start,  {:include_blank => true}, {:id=>"startdrop" } %>

如何在此Rails 2选择表单中设置选定的选项？

2 个答案: