在看一个老视频

http://railscasts.com/episodes/38-multibutton-form

new.rhtml 会根据 params[:preview_button] 来显示@project.description。

view 不是只能访问 controller 中的实例变量吗？求答疑解惑

projects/new.rhtml

<% if params[:preview_button] %>
  <%= textilize @project.description %>
<% end %>
...
<%= submit_tag 'Create' %>
<%= submit_tag 'Preview', :name => 'preview_button' %>

projects_controller.rb

def create
  @project = Project.new(params[:project])
  if params[:preview_button] || [email protected]
    render :action => 'new'
  else
    flash[:notice] = "Successfully created project."
    redirect_to project_path(@project)
  end
end