Ruby on Rails-模型验证

Question

I have a problem with simple model validation. Entering materials without SKU is getting me error message:

NoMethodError in Materials#create undefined method `empty?' for nil:NilClass

material.rb:

class Material < ActiveRecord::Base
  validates :sku, :presence => true
end

materials_controler.rb (create part only):

# POST /materials
  # POST /materials.json
  def create
    @material = Material.new(material_params)


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

Answer 1

Your @units instance variable is nil in create action. You should set it the same way as you do in new or edit actions after your records fails validation.

Answer 2

在您的create方法中也定义@units