Question

我想在用户编辑表单时显示我的下拉表单选定选项值。现在它显示第一个选项（在这种情况下是一个空白选项）。

表格

<%= f.select(:condition, options_for_select([["Brand New", "Brand New"], ["Pre-owned", "Pre-owned"]]), :include_blank => true, :selected => params[:condition]) %>

HTML输出

<select id="product_condition" name="product[condition]">
    <option value=""></option>
    <option value="Brand New">Brand New</option>
    <option value="Pre-owned">Pre-owned</option>
</select>

JSON

{
    id: 2,
    condition: "Pre-owned",
}

感谢。

Answer 1

<%= f.select(:condition, options_for_select([["Brand New", "Brand New"], ["Pre-owned", "Pre-owned"]], :selected => f.object.condition), :include_blank => true) %>

Answer 2

检查options_for_select文档，您会发现最后一个参数是所选选项。

options_for_select(container, selected = nil)

在你的情况下

<%= f.select(:condition, options_for_select([["Brand New", "Brand New"], ["Pre-owned", "Pre-owned"]], params[:condition]), :include_blank => true) %>

假设params[:condition]包含当前选定的值，并且该值与select标记中的相应值匹配。

换句话说，要选择"Pre-owned"，params[:condition]必须包含"Pre-owned"。

Answer 3

此表单多个下拉列表，但用户只能选择一个，并且如果您编辑和显示方法仅显示一个记录。

<%= form.label :Hobbies%>

<%= form.select(:hobbies, options_for_select(%w[cricket football hockey reading], :selected => form.object.hobbies )) %><br><br>

Answer 4

<%= f.select :condition, options_for_select([["Brand New", "Brand New"], ["Pre-owned", "Pre-owned"]], f.object.condition), {:include_blank => true} %>

编辑表单时显示所选选项（Rails 4）

4 个答案: