Ruby on rails 如何填充下拉列表[rails4]

所以，我有一个应用程序，可以让用户上传和评论歌曲。不过，我想添加一个流派类别。当用户上传歌曲时，他们可以选择歌曲的类型。这将有助于我添加搜索

有关代码的快速概述，请参见：www.github.com/apane/leap

我猜我会在db中添加一个流派表，并将其与歌曲关联，例如：

体裁属于歌曲，一首歌曲有很多体裁

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但在那之后，我被难住了。如何填充“类型”下拉列表

将流派表添加到数据库后，可以执行以下操作：

<%= collection_select(:song, :genre_id, Genre.all, :id, :name) %>

其中：歌曲是指您上传歌曲的表单

rails g model genre name
rails g model genre_song genre:belongs_to song:belongs_to
rake db:migrate

模型/流派.rb

has_many :genre_songs
has_many :songs, through: :genre_song

has_many :genre_songs
has_many :genres, through: :genre_song

def self.tagged_with(name)
  Genre.find_by_name!(name).songs
end

def tag_list
  genres.map(&:name).join(", ")
end

def tag_list=(names)
  self.genres = names.split(",").map do |n|
    Genre.where(name: n.strip).first_or_create!
  end
end

Genres: <%= raw song.genres.map(&:name).map { |t| link_to t, genre_path(t) }.join(', ') %>

<div class="field">
  <%= f.label :tag_list, "Genres (separated by commas)" %><br />
  <%= f.text_field :tag_list %>
</div>

型号/歌曲.rb

has_many :genre_songs
has_many :songs, through: :genre_song

has_many :genre_songs
has_many :genres, through: :genre_song

def self.tagged_with(name)
  Genre.find_by_name!(name).songs
end

def tag_list
  genres.map(&:name).join(", ")
end

def tag_list=(names)
  self.genres = names.split(",").map do |n|
    Genre.where(name: n.strip).first_or_create!
  end
end

Genres: <%= raw song.genres.map(&:name).map { |t| link_to t, genre_path(t) }.join(', ') %>

<div class="field">
  <%= f.label :tag_list, "Genres (separated by commas)" %><br />
  <%= f.text_field :tag_list %>
</div>

歌曲/index.html.erb

has_many :genre_songs
has_many :songs, through: :genre_song

has_many :genre_songs
has_many :genres, through: :genre_song

def self.tagged_with(name)
  Genre.find_by_name!(name).songs
end

def tag_list
  genres.map(&:name).join(", ")
end

def tag_list=(names)
  self.genres = names.split(",").map do |n|
    Genre.where(name: n.strip).first_or_create!
  end
end

Genres: <%= raw song.genres.map(&:name).map { |t| link_to t, genre_path(t) }.join(', ') %>

<div class="field">
  <%= f.label :tag_list, "Genres (separated by commas)" %><br />
  <%= f.text_field :tag_list %>
</div>

类型：

歌曲/\u form.html.erb

has_many :genre_songs
has_many :songs, through: :genre_song

has_many :genre_songs
has_many :genres, through: :genre_song

def self.tagged_with(name)
  Genre.find_by_name!(name).songs
end

def tag_list
  genres.map(&:name).join(", ")
end

def tag_list=(names)
  self.genres = names.split(",").map do |n|
    Genre.where(name: n.strip).first_or_create!
  end
end

Genres: <%= raw song.genres.map(&:name).map { |t| link_to t, genre_path(t) }.join(', ') %>

<div class="field">
  <%= f.label :tag_list, "Genres (separated by commas)" %><br />
  <%= f.text_field :tag_list %>
</div>

歌曲\u控制器.rb

has_many :genre_songs
has_many :songs, through: :genre_song

has_many :genre_songs
has_many :genres, through: :genre_song

def self.tagged_with(name)
  Genre.find_by_name!(name).songs
end

def tag_list
  genres.map(&:name).join(", ")
end

def tag_list=(names)
  self.genres = names.split(",").map do |n|
    Genre.where(name: n.strip).first_or_create!
  end
end

Genres: <%= raw song.genres.map(&:name).map { |t| link_to t, genre_path(t) }.join(', ') %>

<div class="field">
  <%= f.label :tag_list, "Genres (separated by commas)" %><br />
  <%= f.text_field :tag_list %>
</div>

---

添加

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到许可参数

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