Question

我有两个控制器 - ItemsController和TradesController。我正在@trade ItemsController操作中构建#show，该操作会使用表单发送到TradesController #create操作。

class ItemsController < ApplicationController
 def show
  @item = Item.friendly.find(params[:id])
  @trade = current_user.requested_trades.build
  @approved_trades = @item.trades
  respond_to do |format|
   format.html
   format.json { render :json => @items.to_json(:methods => [:image_url]) }
  end
end

class TradesController < ApplicationController
 def create
  @trade = current_user.requested_trades.build(trade_params)
  respond_to do |format|
   if @trade.save
    format.html { redirect_to @trade, notice: "Your request for trade has been submitted. You will be notified once it is approved or denied." }
    format.json { render :index, status: :created, location: @trade }
   else
    format.html { redirect_to @trade, notice: "Pick another amount" }
   end
  end
 end

 private
 def trade_params
  params.require(:trade).permit(:trade_requester, :trade_recipient, :wanted_item, :collateral_item, :shares)
 end
end

然后这是我的Trade模型

class Trade < ActiveRecord::Base
 belongs_to :trade_requester, class_name: "User"
 belongs_to :trade_recipient, class_name: "User"
 belongs_to :wanted_item, class_name: "Item"
 belongs_to :collateral_item, class_name: "Item"
end

以下是Item's show视图中的表单：

<%= form_for(@trade) do |f| %>                  
 <%= f.hidden_field :wanted_item, value: @item.id %>
 <div class="field">
  <%= f.text_field :shares, placeholder: "Pick a number between 1 and #{@item.shares}" %>
  <%= f.submit "Trade", class: "button minty-button wide-button" %>     
 </div>
<% end %>

ItemsController TradesController帖子的create帖子的上述代码，但我收到的错误是ActiveRecord::AssociationTypeMismatch in TradesController#createItem(#70095717466760) expected, got String(#70095657672800)

为什么期待Item？似乎如果@trade创建导致错误，那么它应该重定向到@trade。

Answer 1

快速解决方案是将隐藏字段从:wanted_item更改为:wanted_item_id：

  <%= form_for(@trade) do |f| %>                  
    <%= f.hidden_field :wanted_item_id, value: @item.id %>
    <div class="field">
      <%= f.text_field :shares, placeholder: "Pick a number between 1 and #{@item.shares}" %>
      <%= f.submit "Trade", class: "button minty-button wide-button" %>     
    </div>
  <% end %>

另外，请确保trade_params方法允许wanted_item_id：

def trade_params
  params.require(:trade).permit(:trade_requester, :trade_recipient, :wanted_item_id, :collateral_item_id, :shares)
end

您可能在另一种形式下遇到与:collateral_item类似的问题。

什么导致我的控制器中的这个AssociationTypeMismatch？

1 个答案: