參數是丟失或爲空值：類

Question

我試着基礎上的「成長」，即時通訊創造（一個花園管理工具」

但是我發現了以下錯誤的標題就可以創建一個新的類別：

「PARAM缺失或爲空值：類別」

[編輯]這是代碼是如何固定爲每評價的建議：

除去@grow = Grow.new(grow_params.merge(category: Category.create(cat_params)))

與@grow = Grow.new(grow_params)

更換，並在成長型加

after_create do Category.create(name: self.title) end

及其固定。

class GrowsController < ApplicationController 
before_action :set_grow, only: [:show, :edit, :update, :destroy] 


def index 
    @grows = Grow.all 
end 


def show 
end 


def new 
    @grow = Grow.new 
end 


def edit 
end 


def create 
    @grow = Grow.new(grow_params.merge(category: Category.create(cat_params))) 

    respond_to do |format| 
    if @grow.save 
     format.html { redirect_to @grow, notice: 'Grow was successfully created.' } 
     format.json { render :show, status: :created, location: @grow } 
    else 
     format.html { render :new } 
     format.json { render json: @grow.errors, status: :unprocessable_entity } 
    end 
    end 
end 

# PATCH/PUT /grows/1 
# PATCH/PUT /grows/1.json 
def update 
    respond_to do |format| 
    if @grow.update(grow_params) 
     format.html { redirect_to @grow, notice: 'Grow was successfully updated.' } 
     format.json { render :show, status: :ok, location: @grow } 
    else 
     format.html { render :edit } 
     format.json { render json: @grow.errors, status: :unprocessable_entity } 
    end 
    end 
end 

# DELETE /grows/1 
# DELETE /grows/1.json 
def destroy 
    @grow.destroy 
    respond_to do |format| 
    format.html { redirect_to grows_url, notice: 'Grow was successfully destroyed.' } 
    format.json { head :no_content } 
    end 
    end 

private 
    # Use callbacks to share common setup or constraints between actions. 

    def set_grow 
    @grow = Grow.find(params[:id]) 
    end 
    def cat_params 
    params.require(:category).permit(:name) 
    end 
    def grow_params 
     params.require(:grow).permit(:title, :notes, :category_id) 
    end 
    end 

我只是想在grow.title新的類別名稱 傳遞但是林不知道如何實現它。

Answer 1

在你create方法離開說法是 @grow = Grow.new(grow_params)

，並在您Grow模型，編寫after_create回調

在其中創建您Category像Category.create(name: self.title)