Ruby on Rails的：在Rails的3.0.10

Question

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) 

上方没有方法错误是创业板名单..

我保持这将对每一项任务，但命令task=Todo.tasks.new导致在规定的子任务的基本待办事项没有方法错误

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 > 

Answer 1

谢谢你！我得到了答案，我在创建实例时犯了一个错误，我试着这样做：t = Todo.new t = Todo.tasks.new而不是：t = Todo.new x = t.tasks。

Answer 2

您可能会无意中在类而不是实例上调用tasks。试试这个：

task=todo.tasks.new 

Answer 3

好像这是你在做

todo=todo.first一个简单的拼写错误，但什么是第二todo？堂妹好像你还没有定义它，但在第二个例子中，你做

todo=Todo.first 

检查你的资本“T”做第二个例子，尝试纠正或者你可以尝试

todo = Todo.all.first 

（假设你有一个叫做藤一AR模型）

欢呼