ruby on rails - Dropdown selector, selected option -

i using ruby on rails version 3. have defined following helper method selector:

  def current_user_selector     collection_select(:user, :id, user.all, :id, :name, {:prompt => "select user"});   end 

i have introduced aforementioned selector in index.html.erb:

... <%= current_user_selector %> ... 

i've read somewhere selected option dropdown menu accessed in controller with:

selected_user = params[user][id] 

i have added above line in several actions of controller keep getting exceptions.

currently have in following action:

  # /users/:id/click   # /users/:id/click.xml   def click     @user = user.find(params[:id])     @users_to_click = user.where("clicks_given - clicks_received >= ?", -5).order("clicks_given - clicks_received")     selected_user = params[user][id]      respond_to |format|       format.html # click.html.erb       format.xml  { render :xml => @user }     end   end 

my question is, how , selected user of dropdown menu.

naren sisodiya led me following exception:

you have nil object when didn't expect it! might have expected instance of activerecord::base. error occurred while evaluating nil.[] 

params[:user][:id] give id of selected user, need find user using id.

selected_user = user.find(params[:user][:id]) 

edit:

also make sure accessing params[:user][:id] instead params[user][id]

update:

you need pass selected value server, mentioned have button invokes click action. can create dropdown , 1 submit button; as

<%= form_tag('/click',:method=>'get') -%>  <%= current_user_selector %>  <%= submit_tag 'get selected' %> <% end -%>