管理员的作业页面报500

app/views/admin/homework.html.erb

@@ -29,6 +29,7 @@
     <tbody>
       <%@count=@page*30 %>
       <% for homework in @homework do %>
+          <% unless homework.nil? %>
           <% @count+=1 %>
           <tr>
             <td align="center">
@@ -54,6 +55,7 @@
               <%=format_date(homework.end_time) %>
             </td>
           </tr>
+          <% end %>
       <% end %>
     </tbody>
   </table>