我的产品模型包含一些参数（price，category_id，image等）。
在部分表单中创建新产品时，正在通过select_tag选择类别，并通过Carrierwave图像上传程序上传图片。当我发送用户在crop.html.erb文件中裁剪上传的图像时，会发生不好的事情。有用户裁剪图像，点击提交，它使用路径作为更新（不太确定哪个HTTP协议），并被重定向到产品编辑页面，因为产品以某种方式丢失了category_id参数。表单显示错误以选择类别（input_fields中的所有其他参数不会丢失）。
我的尝试就像定义crop方法并在那里设置类别，但没有运气......
products_controller.rb：
def edit
@categories = Category.all
end
def create
@product = Product.new(product_params)
@product.category_id = params[:category_id]
@product.user_id = current_user.id
respond_to do |format|
if @product.save
if params[:product][:image].present?
format.html { render :crop }
else
format.html { redirect_to @product, notice: 'Product was successfully created.' }
format.json { render :show, status: :created, location: @product }
end
else
format.html { render :new }
format.json { render json: @product.errors, status: :unprocessable_entity }
end
end
end
def update
@product.category_id = params[:category_id]
respond_to do |format|
if @product.update(product_params)
if params[:product][:image].present?
format.html { render :crop }
else
format.html { redirect_to @product, notice: 'Product was successfully updated.' }
format.json { render :show, status: :ok, location: @product }
@products = Product.all
ActionCable.server.broadcast 'products',
html: render_to_string('store/index', layout: false)
end
else
format.html { render :edit }
format.json { render json: @product.errors, status: :unprocessable_entity }
end
end
end
crop.html.erb（在产品文件夹中）：
<%= image_tag @product.image_url(:large), id: "cropbox" %>
<h4>Preview</h4>
<div style="width:300px; height:200px; overflow:hidden;">
<%= image_tag @product.image.url(:large), :id => "preview" %>
</div>
<%= form_for @product do |f| %>
<% %w[x y w h].each do |attribute| %>
<%= f.hidden_field "crop_#{attribute}" %>
<% end %>
<div class="actions">
<%= f.submit "Crop" %>
</div>
<% end %>
我还没有尝试设置存储category_id的回调，但我不知道这是个好主意吗？有帮助吗？谢谢！
编辑 - 也添加了一个部分表单，但它工作正常 - 只是为了你的好奇心：
<%= form_for(product, hmtl: { multipart: true } ) do |f| %>
...
<div class="field">
<%= f.label :category %>
<%= select_tag(:category_id, options_from_collection_for_select(Category.all, :id, :name, @product.category_id), include_blank: "Select Category") %>
</div>
更新
记录这些操作：
Started GET "/products/new" for ::1 at 2016-12-15 09:03:31 +0200
Processing by ProductsController#new as HTML
[1m[36mCart Load (0.4ms)[0m [1m[34mSELECT "carts".* FROM "carts" WHERE "carts"."id" = $1 LIMIT $2[0m [["id", 5], ["LIMIT", 1]]
[1m[36mCACHE (0.0ms)[0m [1m[34mSELECT "carts".* FROM "carts" WHERE "carts"."id" = $1 LIMIT $2[0m [["id", 5], ["LIMIT", 1]]
[1m[36mUser Load (2.0ms)[0m [1m[34mSELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2[0m [["id", 1], ["LIMIT", 1]]
Rendering products/new.html.erb within layouts/application
[1m[36mCategory Load (0.4ms)[0m [1m[34mSELECT "categories".* FROM "categories"[0m
Rendered products/_form.html.erb (6.2ms)
Rendered products/new.html.erb within layouts/application (11.2ms)
[1m[36mCACHE (0.0ms)[0m [1m[34mSELECT "categories".* FROM "categories"[0m
[1m[36mLineItem Load (0.5ms)[0m [1m[34mSELECT "line_items".* FROM "line_items" WHERE "line_items"."cart_id" = $1[0m [["cart_id", 5]]
Completed 200 OK in 127ms (Views: 113.2ms | ActiveRecord: 3.3ms)
Started POST "/products" for ::1 at 2016-12-15 09:03:40 +0200
Processing by ProductsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"eWZuqL6AqcN8wknjEL115ax9uBnpY4b9eP0o2xN2aPntd61YKyc4Ym1lUgjV1YrXfZbPr57HANXy7Kz5swCtlg==", "product"=>{"title"=>"kj", "description"=>"kj", "image"=>#<ActionDispatch::Http::UploadedFile:0x007fe40ba4abe0 @tempfile=#<Tempfile:/var/folders/dn/zq9x2jkd4856kwhfj5gbz2tc0000gn/T/RackMultipart20161215-3987-1adfacs.png>, @original_filename="Screen Shot 2016-12-05 at 09.14.48.png", @content_type="image/png", @headers="Content-Disposition: form-data; name=\"product[image]\"; filename=\"Screen Shot 2016-12-05 at 09.14.48.png\"\r\nContent-Type: image/png\r\n">, "price"=>"98", "quantity"=>"98"}, "category_id"=>"1", "commit"=>"Create Product"}
[1m[36mCart Load (0.3ms)[0m [1m[34mSELECT "carts".* FROM "carts" WHERE "carts"."id" = $1 LIMIT $2[0m [["id", 5], ["LIMIT", 1]]
[1m[36mCACHE (0.0ms)[0m [1m[34mSELECT "carts".* FROM "carts" WHERE "carts"."id" = $1 LIMIT $2[0m [["id", 5], ["LIMIT", 1]]
[1m[36mUser Load (0.7ms)[0m [1m[34mSELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2[0m [["id", 1], ["LIMIT", 1]]
[1m[35m (0.3ms)[0m [1m[35mBEGIN[0m
[1m[36mCategory Load (0.3ms)[0m [1m[34mSELECT "categories".* FROM "categories" WHERE "categories"."id" = $1 LIMIT $2[0m [["id", 1], ["LIMIT", 1]]
[1m[35mSQL (1.0ms)[0m [1m[32mINSERT INTO "products" ("title", "description", "price", "quantity", "created_at", "updated_at", "category_id", "user_id", "image") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9) RETURNING "id"[0m [["title", "kj"], ["description", "kj"], ["price", #<BigDecimal:7fe40ccf9110,'0.98E2',9(18)>], ["quantity", 98], ["created_at", 2016-12-15 07:03:41 UTC], ["updated_at", 2016-12-15 07:03:41 UTC], ["category_id", "1"], ["user_id", 1], ["image", "Screen_Shot_2016-12-05_at_09.14.48.png"]]
[1m[35m (3.1ms)[0m [1m[35mCOMMIT[0m
Rendering products/crop.html.erb within layouts/application
Rendered products/crop.html.erb within layouts/application (3.1ms)
[1m[36mCategory Load (0.7ms)[0m [1m[34mSELECT "categories".* FROM "categories"[0m
[1m[36mLineItem Load (0.3ms)[0m [1m[34mSELECT "line_items".* FROM "line_items" WHERE "line_items"."cart_id" = $1[0m [["cart_id", 5]]
Completed 200 OK in 957ms (Views: 127.8ms | ActiveRecord: 6.7ms)
所以我注意到它在没有特定ID的情况下呈现products/crop.html.erb，所以我添加了我的路线：
resources :products do
get 'crop', on: :member
end
且products_controller创建动作：
...
respond_to do |format|
if @product.save
if params[:product][:image].present?
format.html { render crop_product_path(@product) }
else
...
仍然是同一个错误，必须选择一个类别。
需要注意的是 - 如果只是去编辑产品（但不是来自crop动作），那么类别会按照假设... ...
答案 0 :(得分：1)
由于表单仅提交其中定义的收集参数，因此您应添加隐藏字段以在category_id视图中设置crop.html
<%= image_tag @product.image_url(:large), id: "cropbox" %>
<h4>Preview</h4>
<div style="width:300px; height:200px; overflow:hidden;">
<%= image_tag @product.image.url(:large), :id => "preview" %>
</div>
<%= form_for @product do |f| %>
<% %w[x y w h].each do |attribute| %>
<%= f.hidden_field "crop_#{attribute}" %>
<% end %>
<%= f.hidden_field :category_id %>
<div class="actions">
<%= f.submit "Crop" %>
</div>
<% end %>
现在，当您提交表单时，您将在category_id
params[:product][:category_id]