simple_form关联未正确更新

Question

In Rails 4.0.2, I have the following models/relationships:

class User < ActiveRecord::Base
  has_many :client_account_assignments
  has_many :clients, -> { uniq }, through: :client_account_assignments
  ...
end

class Client < ActiveRecord::Base
  has_many :client_account_assignments
  has_many :users, -> { uniq }, through: :client_account_assignments
  ...
end

In the edit.html.haml view for users, I have the following form:

= simple_form_for @user do |f|
  = f.association :clients, as: :select, collection: Client.all, value_method: :id, label_method: :name, include_blank: false, input_html: {data: {placeholder: "Choose..."}}

Adding clients to a user works as expected. However, deselecting one or more clients does not work correctly. For example:

1. @user.id => 1

2. @user.clients.map(&:id) => [70, 74, 76, 71, 72, 73, 75]

3. Navigate to users/1/edit

4. Deselect all clients except the client with id of 76.

5. Set breakpoint in UsersController#update .

6. Click "save".

7. params[:user][:client_ids] => ["", "76", "", "70", "71", "72", "73", "74", "75", "76"]

Why are all the previously-selected, now-unselected client ids being passed in the params?

Another example:

1. @user.id => 1

2. @user.clients.map(&:id) => [70]

3. Navigate to users/1/edit

4. Deselect all clients, except for the clients with ids of 71 and 72.

5. Click "save".

6. params[:user][:client_ids] => ["", "71", "72", "", "70"]

Again, why is the old client id (ie, 70) still appearing in the params?

Answer 1

原来这是一个简单的答案：我不小心在视图上多次渲染了客户输入，因此保留了旧值。