不允许的参数错误（强参数）

Question

我有一个表格：

= simple_form_for @character do |f|
    = f.input :name
    = f.input :description
    = f.simple_fields_for @movie_characters do |fmc|
        = fmc.association :movie, value_method: :id, label_method: :title
    = f.submit

这里的关系是 Character 有很多 MovieCharacter 和 MovieCharacter belongs_to Movie。

我从这个表单中得到的参数如下所示：

{"utf8"=>"✓", "_method"=>"patch", "authenticity_token"=>"6d8n1Z5AC3nF/cqzTInnMr5TyRhZFcGV8ssf5CsNkjskiD9lUL10nVDYeV4i0yS85Q87yNcIi+coFFDf0mpZ4w==", "character"=>{"name"=>"Joker", "description"=>"best villain ever", "movie_character"=>{"movie_id"=>"1"}}, "commit"=>"Update Character", "controller"=>"characters", "action"=>"update", "id"=>"1"}

character_params 方法如下所示：

def character_params
        params.require(:character).permit(:name, :description, movie_characters_attributes: [:movie_id, :character_id])
    end

不幸的是，在控制器中调用此方法时，我收到“Unpermitted parameter: movie_character”警告。 我也试过了

def character_params
            params.require(:character).permit(:name, :description, movie_characters: [:movie_id, :character_id])
        end

但效果是一样的。你能告诉我为什么它不起作用吗？

更新：

class Character < ActiveRecord::Base
    has_many :movie_characters

    accepts_nested_attributes_for :movie_characters
end

class MovieCharacter < ActiveRecord::Base
  belongs_to :character
  belongs_to :movie
end

Answer 1

你有一个错字。应该是：

def character_params
    params.require(:character).permit(:name, :description, movie_character_attributes: [:movie_id, :character_id])
end

movie_characters_attributes 中没有“s”。