Merge branch 'szzh' of http://repository.trustie.net/xianbo/trustie2 into szzh

app/helpers/files_helper.rb

@@ -48,7 +48,7 @@ module FilesHelper
   def courses_check_box_tags(name,courses,current_course,attachment)
     s = ''
     courses.each do |course|
-      if !(attachment.container_type && attachment.container_id == course.id)  && is_course_teacher(User.current,course) && course_in_current_or_next_term(course)
+      if !course_contains_attachment?(course,attachment)  && is_course_teacher(User.current,course) && course_in_current_or_next_term(course)
         s << "<label>#{ check_box_tag name, course.id, false, :id => nil } #{h course.name}</label>&nbsp;[#{get_course_term course}]<br/>"
       end
     end