AssociationTypeMismatch爲collection_check_boxes

Question

控制器

class PlayerProfilesController < InheritedResources::Base 

    def show 
     @player_profile = PlayerProfile.find(params[:id]) 
    end 
end 

模型

class PlayerProfile < ActiveRecord::Base 

    has_many :playing_roles, :dependent => :destroy 
    has_many :player_roles, through: :playing_roles 

end 

class PlayerRole < ActiveRecord::Base 

    has_many :playing_roles, :dependent => :destroy 
    has_many :player_profiles, through: :playing_roles 

end 

class PlayingRole < ActiveRecord::Base 
    belongs_to :player_profile 
    belongs_to :player_role 

end 

show.html.erb

<%=collection_check_boxes(:player_profile, :playing_roles, PlayerRole.all, :id, :name)%> 

collection_check_boxes（文檔）產生

HTML的兩個複選框

<input id="player_profile_playing_roles_1" name="player_profile[playing_roles][]" type="checkbox" value="1" class="hidden-field"> 
<span class="custom checkbox checked"></span> 
<label for="player_profile_playing_roles_1">Striker</label> 

<input id="player_profile_playing_roles_2" name="player_profile[playing_roles][]" type="checkbox" value="2" class="hidden-field"> 
<span class="custom checkbox"></span> 
<label for="player_profile_playing_roles_2">Midfielder</label> 
<input name="player_profile[playing_roles][]" type="hidden" value=""> 

它似乎正確地顯示所有，但是當我點擊提交按鈕，我得到這個錯誤：

Answer 1

對不起，我以爲這雖然很複雜，但我不認爲這是事實。

您正在告訴collection_check_boxes期待:playing_roles，但隨後通過PlayerRole.all傳遞PlayerRoles的集合。這是不匹配的。 AssociationTypeMismatch是當你告訴一個物體關聯一隻鴨子，但是然後將它傳給一架直升機。

你需要這樣做：

<%= collection_check_boxes(:player_profile, :player_role_ids, PlayerRole.all, :id, :name) %> 

你告訴它期望:player_role_ids，你通過它的PlayerRole.all的集合與值法:id和文本方法:name。

然後，在更新中，它會將這些ID保存到Player上的player_role_ids屬性，從而導致關聯生成。

參見： Rails has_many :through and collection_select with multiple