消息列表报500

app/views/users/_join_course_course_message.html.erb

@@ -5,7 +5,7 @@
 </li>
 <li class="<%=(ma.status == 0 || ma.status.nil?) ? 'homepageHomeworkContent2' : 'homepageHomeworkContent' %> fl">
   <a href="javascript:void(0);" class="newsGrey">
-    <%= link_to User.find(ma.course_message_id).name+"申请成为课程\""+"#{Course.find(ma.course_id).name}"+"\"的"+"#{ma.content.include?('9') ? "教师" : "教辅"}", user_path(User.find(ma.course_message_id), :course_id => ma.course_id),
+    <%= link_to User.find(ma.course_message_id).name+"申请成为课程\""+"#{Course.find(ma.course_id).name}"+"\"的"+"#{ma.content && ma.content.include?('9') ? "教师" : "教辅"}", user_path(User.find(ma.course_message_id), :course_id => ma.course_id),
                 :class => "#{ma.viewed==0 ? "newsBlack" : "newsGrey"}", :target => '_blank' %>
     <!--:onmouseover => "message_titile_show($(this),event)",-->
     <!--:onmouseout => "message_titile_hide($(this))" %>-->