Question

Noob在这里提问，但我认为它也可以帮助其他人，

我从表单（在视图中）和我的控制器中获取数据我想使用此字段：initialgpa并创建一个新字段：normalisedgpa然后将其传递回数据库。但是A）我的数据库永远不会更新和B）当我将乘法加2时，我得到这个错误未定义的方法＆＃39; *＆＃39;为零：NilClass

以下是我的控制器代码

def update 
    @studentprofile = StudentProfile.find_by(id: params[:id])
    @studentprofile.update_attributes(student_profile_params)
    redirect_to @studentprofile
end


def student_profile_params
        params[:normalisedgpa] = params[:initialgpa].to_s * 2

        params.require(:student_profile).permit(:status,:name,:imagethumbnail,:aboutme, :country, :state, :city,:language, :age,:gender,:initialgpa,:normalisedgpa,:universityname,:degree ,:degreetype ,:countryofdegree,:workexperience ,:wantstoworkin,:hasworkexperiencein,:permissiontoworkin,:currentlyemployed,:referencesuponrequest ,:worktype,:monthsspentabroadworking,:monthsspentabroadliving,:charitywork)
end

我也试过放置＆＃34; params [：normalisedgpa] = params [：initialgpa] * 2＆＃34;在更新方法中，以及删除＆＃34; .to_s＆＃34;没有运气

干杯！

Answer 1

控制器/ student_profiles_controller.rb

def update
  @studentprofile = StudentProfile.find_by(id: params[:id])
  @studentprofile.update(student_profile_params)
  redirect_to @student_profile
end

def student_profile_params
  modified_params = params.require(:student_profile).permit(:status,:name,:imagethumbnail,:aboutme, :country, :state, :city,:language, :age,:gender,:initialgpa,:normalisedgpa,:universityname,:degree ,:degreetype ,:countryofdegree,:workexperience ,:wantstoworkin,:hasworkexperiencein,:permissiontoworkin,:currentlyemployed,:referencesuponrequest ,:worktype,:monthsspentabroadworking,:monthsspentabroadliving,:charitywork)
  modified_params[:normalisedgpa] = modified_params[:initialgpa] * 2
  modified_params
end

<强>推荐

控制器/ student_profiles_controller.rb

def update
  # use camelcase->underscore variable naming (i.e. @student_profile) instead of @studentprofile
  # use .find instead of .find_by so that it will show a Not Found page instead when such StudentProfile does not exist anymore
  @student_profile = StudentProfile.find(params[:id])

  # modifies @student_profile with the param values, but does not save yet to the database
  @student_profile.assign_attributes(student_profile_params)
  # manipulate the values here in the action and do not manipulate the params
  @student_profile.normalisedgpa = @student_profile.initialgpa * 2
  # handle validation errors, rather than silently failing when there is a validation error
  if @student_profile.save # if saving to the database successful
    # use flash messages (this is optional depending on your code)
    redirect_to @student_profile, success: 'Student Profile updated'
  else # if saving to the database not successful
    # the line below is just an example depending on your code
    render :edit
  end
end

private

def student_profile_params
  params.require(:student_profile).permit(:status,:name,:imagethumbnail,:aboutme, :country, :state, :city,:language, :age,:gender,:initialgpa,:normalisedgpa,:universityname,:degree ,:degreetype ,:countryofdegree,:workexperience ,:wantstoworkin,:hasworkexperiencein,:permissiontoworkin,:currentlyemployed,:referencesuponrequest ,:worktype,:monthsspentabroadworking,:monthsspentabroadliving,:charitywork)
end

Answer 2

作为@ Jay-Ar Polidario的上述答案的补充，您可能需要在参数中添加.to_i才能获得成功的数学运算。例如，如果我的sale_price的值为“1”而我只是添加“参数* 3”，则结果将为“111”而不是3（1 * 3 = 3）。

即：

$userId

在控制器中处理表单数据以创建新字段 - Rails

2 个答案: