我怎样才能让钢轨自动填充动态生成的表单？ [英] How can I get rails to automatically populate a dynamically generated form?

问题描述

假设我有一个模型

  class A< ApplicationRecord 
 serialize：vals，Array 
 end 
  

存储一组值。我如何动态填充表单值列表？我的第一个猜测是写出

 <％= @ a.vals.each_with_index do | v，i | ％GT; 
<％= f.text_field：hints％> 
<％end％> 
  

但是这给了我错误。

解决方案

提交此表格

 <％= form_for @a do | f | ％GT; 
 <％@ a.vals.each do | val | ％GT; 
<％= f.text_field：vals，value：val，multiple：true％> 
<％end％> 
 
<％= f.submit％> 
<％end％> 
  

传递a=> {vals=> [第一个，第二个，第三个]} 查看 A 的实例中的 vals ，而不是类 A $ b

关于 serialize 的注意事项（更多的评论说它看起来错了）我从来没有用过它， serialize：vals，Array 似乎对我有用

  A.create（vals：['hint 1'，'hint 2']）; A.last.vals 
＃（0.2ms）BEGIN 
＃SQL（0.4ms）INSERT INTO ... [[vals，--- \ n-hint 1 \\\
-提示2 \\\
] ... 
＃（0.6ms）COMMIT 
＃A Load（0.3ms）SELECTas。* FROMasORDER BYas。id DESC LIMIT $ 1 [[LIMIT，1]] 
＃=> [提示1，提示2] 
  

Let's say I have a model

class A < ApplicationRecord
  serialize :vals, Array
end

which stores an array of values. How can I dynamically populate a list of form values? My first guess was to write

<%= @a.vals.each_with_index do |v, i| %>
  <%= f.text_field :hints %>
<% end %>

but this is giving me errors.

解决方案

Submitting this form

<%= form_for @a do |f| %>
  <% @a.vals.each do |val| %>
    <%= f.text_field :vals, value: val, multiple: true %>
  <% end %>

  <%= f.submit %>
<% end %>

passes "a"=>{"vals"=>["first", "second", "third"]} in the params to the controller.

As mentioned in the comments, you want to look at the vals from an instance of A not the class A.

Note about the serialize (more for the comments saying it looks wrong) I had never used it, that serialize :vals, Array seems to be working for me

A.create(vals: ['hint 1', 'hint 2']); A.last.vals
#   (0.2ms)  BEGIN
#   SQL (0.4ms)  INSERT INTO ... [["vals", "---\n- hint 1\n- hint 2\n"]...
#   (0.6ms)  COMMIT
#   A Load (0.3ms)  SELECT  "as".* FROM "as" ORDER BY "as"."id" DESC LIMIT $1  [["LIMIT", 1]]
# => ["hint 1", "hint 2"]

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