我不能更改標記類

Question

我有一個導航面板。如果我點擊它，我想要菜單項的類更改爲active。

%li= { :class => current_page?(admin_roles_path) ? 'active' : nil } 
    = link_to "Roles", admin_roles_path 

，但我得到了以下錯誤：

Haml::SyntaxError in Admin::Roles#index 
Showing /sites/freshapp/app/views/layouts/_sidebar.html.haml where line #7 raised: 

Illegal nesting: content can't be both given on the same line as %li and nested within it. 

Answer 1

你不需要你%li後=和你有太多玉米粥空格/製表符。 （Haml是一種嵌套語言，標籤/空格的數量很重要）。這樣做：

%li{ :class => current_page?(admin_roles_path) ? 'active' : nil } 
    = link_to "Roles", admin_roles_path 

Answer 2

試試這個（你不需要=%li後）

%li{ :class => current_page?(admin_roles_path) ? 'active' : nil } 
    = link_to "Roles", admin_roles_path 

Answer 3

試試這個

%li{ :class => "#{current_page?(admin_roles_path) ? 'active' : nil}"} 
    = link_to "Roles", admin_roles_path