当我尝试添加名为decrement的按钮并实现它时，以下是我得到的错误
No route matches {:controller=>"line_items", :product_id=>#<Product id: 2, title: "Harry Potter", description: "Its drama cum adventure cum suspense cum thriller, ...", image_url: "harry-potter_25.png", price: #<BigDecimal:b068140,'0.1E3',4(8)>, created_at: "2013-03-15 07:21:26", updated_at: "2013-03-18 11:57:13">, :action=>"decrement"}
答案 0 :(得分：0)
如果您将button_to的实现代码与错误一起粘贴，将会有所帮助。
此外，您似乎在针对product_id
的button_to调用中传递了整个产品对象#<Product id: 2, title: "Harry Potter", description: "Its drama cum adventure cum suspense cum thriller, ...", image_url: "harry-potter_25.png", price: #<BigDecimal:b068140,'0.1E3',4(8)>
只需尝试使用product.id
答案 1 :(得分：0)
将<{1}}替换为按钮路径中的:product_id => product
:product_id => product.id