班级成员列表报500

app/models/user.rb

@@ -1237,6 +1237,16 @@ class User < Principal
     Thread.current[:current_user] ||= User.anonymous
   end
 
+  def user_real_extension
+    ue = self.user_extensions
+    if ue.nil?
+      ue = UserExtensions.new
+      ue.user_id = self.id
+      ue.save
+    end
+    ue
+  end
+
   # Returns the anonymous user.  If the anonymous user does not exist, it is created.  There can be only
   # one anonymous user per database.
   def self.anonymous

app/views/courses/_new_member_list.html.erb

@@ -83,7 +83,7 @@
           <%= link_to user.show_name, user_path(user), :class => 'fl sy_class_users_st_name' ,:title => "#{user.show_name}", :target => '_blank' %>
         </td>
         <td>
-          <span class="sy_class_users_st_num" title="<%= user.user_extensions.student_id %>"><%= user.user_extensions.student_id %></span>
+          <span class="sy_class_users_st_num" title="<%= user.user_real_extension.student_id %>"><%= user.user_real_extension.student_id %></span>
         </td>
         <td>
           <% if !is_teacher && User.current.id != member.user_id && course_has_score_open_common_homework(@course) %>