1 
abstract (1.0.0)
actionmailer (3.2.2, 3.0.10, 3.0.5, 3.0.3, 2.3.5, 2.1.0)
actionpack (3.2.2, 3.0.10, 3.0.5, 3.0.3, 3.0.0.beta3, 2.3.5, 2.1.0)
activemodel (3.2.2, 3.0.10, 3.0.5, 3.0.3, 3.0.0.beta3)
activerecord (3.0.10)
activeresource (3.2.2, 3.0.10, 3.0.5, 3.0.3, 2.3.5, 2.1.0)
activesupport (3.2.2, 3.0.10, 3.0.5, 3.0.3, 3.0.0.beta3, 2.3.5, 2.1.0)
arel (3.0.2, 2.0.10, 2.0.6)
bcrypt-ruby (3.0.1, 2.1.2)
bson (1.1.5)
bson_ext (1.1.5)
builder (3.0.0, 2.1.2)
bundle (0.0.1)
bundler (1.1.3, 1.1.1, 1.1.0)
cancan (1.6.7, 1.4.1)
coffee-rails (3.2.2)
coffee-script (2.2.0)
coffee-script-source (1.3.1, 1.2.0)
devise (2.0.4, 1.5.3, 1.1.5)
erubis (2.7.0, 2.6.6)
execjs (1.3.0)
hike (1.2.1)
i18n (0.6.0, 0.5.0, 0.3.7)
journey (1.0.3)
jquery-rails (2.0.2, 2.0.1)
jquery_datepicker (0.3.4)
json (1.6.6, 1.6.5)
libv8 (3.3.10.4 x86-linux)
mail (2.4.4, 2.2.19, 2.2.12, 2.2.7)
memcache-client (1.8.5)
mime-types (1.18, 1.17.2, 1.16)
mongo (1.1.5)
mongoid (2.0.0.beta.20)
multi_json (1.2.0)
mysql2 (0.3.11)
nifty-generators (0.4.2)
orm_adapter (0.0.7)
polyglot (0.3.3, 0.3.1)
rack (1.4.1, 1.2.5, 1.2.1, 1.1.3, 1.0.1)
rack-cache (1.2)
rack-mount (0.6.14, 0.6.13)
rack-ssl (1.3.2)
rack-test (0.6.1, 0.5.7, 0.5.6)
rails (3.0.10)
railties (3.2.2, 3.0.10, 3.0.5, 3.0.3)
rake (0.9.2.2, 0.8.7)
rdoc (3.12)
rolify (3.1.0)
sass (3.1.15)
sass-rails (3.2.5)
sprockets (2.1.2)
sqlite3 (1.3.5)
therubyracer (0.9.10)
thor (0.14.6)
tilt (1.3.3)
treetop (1.4.10, 1.4.9)
tzinfo (0.3.33, 0.3.32, 0.3.23)
uglifier (1.2.4)
warden (1.1.1, 1.0.3)
will_paginate (3.0.3, 3.0.pre2)

以上是宝石清单..

我正在维护一个基本的待办事项，它将在每个任务中定义子任务，但该命令task=Todo.tasks.new不会导致方法错误

amrit@PC148881:~/mytodos$ rails console
Loading development environment (Rails 3.0.10)
1.9.2-p290 :001 > todo=todo.first
NoMethodError: You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.first
    from (irb):1
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands/console.rb:44:in `start'
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands/console.rb:8:in `start'
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands.rb:23:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'
1.9.2-p290 :002 > todo=Todo.first
 => #<Todo id: 1, name: "Office", description: "work to be completed at office", created_at: "2012-04-17 08:53:35", updated_at: "2012-04-17 08:53:35"> 
1.9.2-p290 :003 > task=Todo.tasks.new
NoMethodError: undefined method `tasks' for #<Class:0xae32588>
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/activerecord-3.0.10/lib/active_record/base.rb:1014:in `method_missing'
    from (irb):3
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands/console.rb:44:in `start'
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands/console.rb:8:in `start'
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands.rb:23:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'
1.9.2-p290 :004 > ^C
1.9.2-p290 :004 > t=Task.new
 => #<Task id: nil, description: nil, due_date: nil, due_time: nil, completed: nil, todo_id: nil, created_at: nil, updated_at: nil> 
1.9.2-p290 :005 > t.description="meeting"
 => "meeting" 
1.9.2-p290 :006 > t.save
 => true 
1.9.2-p290 :007 > task=Todo.tasks.new
NoMethodError: undefined method `tasks' for #<Class:0xae32588>
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/activerecord-3.0.10/lib/active_record/base.rb:1014:in `method_missing'
    from (irb):7
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands/console.rb:44:in `start'
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands/console.rb:8:in `start'
    from /home/amrit/.rvm/gems/ruby-1.9.2-p290@1.9.2/gems/railties-3.0.10/lib/rails/commands.rb:23:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'
1.9.2-p290 :008 >
4

3 回答 3

1

您可能无意中调用tasks了 Class 而不是实例。试试这个：

task=todo.tasks.new
于 2012-04-17T04:40:07.813 回答
0

这似乎是你正在做的一个简单的错字

todo=todo.first, 但什么是第二todo？因为看起来你还没有定义它；在你的第二个例子中你做

todo=Todo.first

检查你用大写“T”做的第二个例子，尝试纠正，或者你可以尝试

todo = Todo.all.first

（假设你有一个名为 Todo 的 AR 模型）

于 2012-04-17T05:58:34.100 回答
0

谢谢 ！！我得到了答案，我在创建我正在尝试的实例时犯了一个错误：t=Todo.new t=Todo.tasks.new 而不是：t=Todo.new x=t.tasks。

于 2012-08-08T10:52:08.320 回答