ruby Rails 模型的“未定义方法”
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"undefined method" for a rails model
提问by Sebastien
I am using Devise with rails and i want to add a method "getAllComments", so i write this :
我正在使用带有 Rails 的设计，我想添加一个方法“getAllComments”，所以我写了这个：
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
# Setup accessible (or protected) attributes for your model
attr_accessible :email, :password, :password_confirmation, :remember_me, :city, :newsletter_register, :birthday, :postal_code,
:address_complement, :address, :lastname, :firstname, :civility
has_many :hotels_comments
class << self # Class methods
def getAllComments
true
end
end
end
And in my controller :
在我的控制器中：
def dashboard
@user = current_user
@comments = @user.getAllComments();
end
And when i go to my url, i got
当我去我的网址时，我得到了
undefined method `getAllComments' for #<User:0x00000008759718>
What i am doing wrong?
我在做什么错？
Thank you
谢谢
回答by Douglas F Shearer
Because getAllCommentsis a class method and you are attempting to access it as an instance method.
因为getAllComments是一个类方法，而您正试图将它作为实例方法访问。
You either need to access it as:
您要么需要通过以下方式访问它：
User.getAllComments
or redefine it as an instance method:
或将其重新定义为实例方法：
class User < ActiveRecord::Base
#...
def getAllComments
true
end
end
def dashboard
@user = current_user
@comments = @user.getAllComments
end
回答by WarHog
As I can see, you make getAllComments as class method through addition it to eigenclass. And you try to call this method from instance.
正如我所看到的，您通过将 getAllComments 添加到 eigenclass 来将它作为类方法。你尝试从实例调用这个方法。
回答by Petr
Content of class << selfmeans class method. It could be shortened as def self.getAllComments
class << self手段类方法的内容。它可以缩短为def self.getAllComments
You should call it User.getAllCommentsand not @user.getAllComments
你应该调用它User.getAllComments而不是@user.getAllComments
回答by Fadhli Rahim
The getAllComments() method that you wrote is a class method
你写的 getAllComments() 方法是一个类方法
So the correct way to call the methods is
所以调用方法的正确方法是
@comments = User.getAllComments
But if you really want to scope the getAllComments to the current user, I recommend you write an instance method
但是如果你真的想把 getAllComments 的范围限定在当前用户，我建议你写一个实例方法
class User < ActiveRecord::Base
..
def getAllComments
// comments implementation
end
So that way you can access the getAllComments method like so:
这样你就可以像这样访问 getAllComments 方法：
@user = current_user
@comments = @user.getAllComments
