后台作业列表：作业班级为空时，作业列表样式错误

app/views/admin/homework.html.erb

@@ -38,11 +38,13 @@
             <td style="white-space: nowrap;overflow: hidden;text-overflow: ellipsis;" class="name" title='<%=homework.name%>'>
               <%=link_to(homework.try(:name), student_work_index_path(:homework => homework.id))%>
             </td>
-            <% if homework.course %>
+
-            <td style="white-space: nowrap;overflow: hidden;text-overflow: ellipsis;" class="name" title='<%=homework.course.name%>'>
+            <td style="white-space: nowrap;overflow: hidden;text-overflow: ellipsis;" class="name" title='<%= homework.course.nil? ? "" : homework.course.name %>'>
-              <%= link_to(homework.course.name, course_path(homework.course.id)) %>
+              <% if homework.course %>
+                <%= link_to homework.course.name, course_path(homework.course.id) %>
+              <% end %>
             </td>
-            <% end %>
+
             <td align="center" style="white-space: nowrap;overflow: hidden;text-overflow: ellipsis;" class="name" title='<% if homework.try(:user).try(:realname) == ' '%><%= homework.try(:user)%><% else %><%=homework.try(:user).try(:realname) %><% end %>'>
               <% if homework.try(:user).try(:realname) == ' '%>
                   <%= link_to(homework.try(:user), user_path(homework.user_id)) %>