[英]Setting has_many :through with a form on rails 3
我正在尝试使用表单为用户创建用户角色,
<%= form_for @user do |f| %>
<%= f.error_messages %>
<p>
<%= f.label :username %><br />
<%= f.text_field :username %>
</p>
<p>
<%= f.label :email, "Email Address" %><br />
<%= f.text_field :email %>
</p>
<p>
<%= f.label :password %><br />
<%= f.password_field :password %>
</p>
<p>
<%= f.label :password_confirmation, "Confirm Password" %><br />
<%= f.password_field :password_confirmation %>
</p>
<% # f.select :roles, Role.all.map {|r| [r.title]} %>
<% Role.all.each do |role| %>
<div>
<%= check_box_tag :role_ids, role.id, @user.roles.include?(role), :name => 'user[role_ids][]' -%>
<%= label_tag :role_ids, role.title -%>
</div>
<% end -%>
<p><%= f.submit (@user.new_record? ? "Sign up" : "Update"), :id => :sign_up %></p>
<% end %>
这是我模型中的关联
class user < ActiveRecord::Base
has_many :assignments
has_many :roles, :through => :assignments
end
class assignment < ActiveRecord::Base
belongs_to :user
belongs_to :role
end
class role < ActiveRecord::Base
has_many :assignments
has_many :users, :through => :assignments
end
通过使用我一开始介绍的表单在用户和角色之间创建分配的方式是什么?
我在用户控制器中的创建动作如下所示:
def create
@user = User.new(params[:user])
if @user.save
session[:user_id] = @user.id
render :action => 'dashboard'
else
render :action => 'new'
end
end
当我发送表格时,出现错误:
UsersController#create中的ActiveRecord :: AssociationTypeMismatch
预期角色(#70331681817580),得到的字符串(#70331650003400)
Request
Parameters:
{"utf8"=>"✓",
"authenticity_token"=>"WHpOW+DmymZ2pWmY9NHSuodf2vjyKdgMNZcc8NvCNa0=",
"user"=>{"username"=>"ioio",
"email"=>"ioio@ioio.com",
"password"=>"[FILTERED]",
"password_confirmation"=>"[FILTERED]",
"roles"=>["2"]}, #### <<< ==== This is the checkbox that I selected for this request.
"commit"=>"Sign up"}
欢迎任何帮助。
使用当前表格并基于:
<%= check_box_tag :role_ids, role.id, @user.roles.include?(role), :name => 'user[role_ids][]' -%>
在提交时,您的参数应该看起来像(注意'role_ids'而不是'roles'):
Request
Parameters:
{"utf8"=>"✓",
"authenticity_token"=>"WHpOW+DmymZ2pWmY9NHSuodf2vjyKdgMNZcc8NvCNa0=",
"user"=>{"username"=>"ioio",
"email"=>"ioio@ioio.com",
"password"=>"[FILTERED]",
"password_confirmation"=>"[FILTERED]",
"role_ids"=>["2"]}, #### <<< ==== This is the checkbox that I selected for this request.
"commit"=>"Sign up"}
如果是这种情况,则必须实例化角色并在控制器中为用户设置它们:
def create
@user = User.new(params[:user])
roles = Role.find(params[:user][:role_ids]) rescue []
@user.roles = roles
if @user.save
session[:user_id] = @user.id
render :action => 'dashboard'
else
render :action => 'new'
end
end
...并类似地:
def update
@user = User.where(:username=>params[:id]).first
roles = Role.find(params[:user][:role_ids]) rescue []
@user.roles = roles
if @user.update_attributes(params[:user])
redirect_to users_url, :notice => "Successfully updated user."
else
render :action => 'edit'
end
end
该错误消息为您提供了提示:为了能够保存用户对象,您首先需要以某种方式创建关联的Role对象。 目前,您只有一个包含角色ID的字符串数组。
您需要在用户模型上使用accepts_nested_attributes_for方法。
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