如何在ASP.NET MVC中直观地指示当前页面？

Question

作为讨论的基础.创建一个标准的ASP.NET MVC Web项目.

它将在母版页中包含两个菜单项:

<div id="menucontainer">
  <ul id="menu">
    <li>
      <%= Html.ActionLink("Home", "Index", "Home")%></li>
    <li>
      <%= Html.ActionLink("About", "About", "Home")%></li>
  </ul>
</div>

如何设置指示当前页面的可视CSS样式.例如,在About页面/控制器中,我基本上想要这样做:

<%= Html.ActionLink("About", "About", "Home", new {class="current"})%></li>

当然,当在主页上时:

<%= Html.ActionLink("Home", "Index", "Home", new {class="current"})%></li>

(CSS样式名称当前在菜单中可视地指示这是当前页面.)

我可以将菜单div从主页面分成内容占位符,但这意味着我必须将菜单放在每个页面上.

任何想法,有一个很好的解决方案吗？

Answer 1

最简单的方法是从ViewContext的RouteData获取当前控制器和操作.请注意签名的更改和使用@来转义关键字.

<% var controller = ViewContext.RouteData.Values["controller"] as string ?? "Home";
   var action = ViewContext.RouteData.Values["action"] as string ?? "Index";
   var page = (controller + ":" + action).ToLower();
 %>

<%= Html.ActionLink( "About", "About", "Home", null,
                     new { @class = page == "home:about" ? "current" : "" ) %>
<%= Html.ActionLink( "Home", "Index", "Home", null,
                     new { @class = page == "home:index" ? "current" : "" ) %>

请注意,您可以将这个HtmlHelper扩展名与@ Jon's结合使用,并使其更清晰.

<%= Html.MenuLink( "About", "About", "Home", null, null, "current" ) %>

MenuActionLink的位置

public static class MenuHelperExtensions
{
     public static string MenuLink( this HtmlHelper helper,
                                    string text,
                                    string action,
                                    string controller,
                                    object routeValues,
                                    object htmlAttributes,
                                    string currentClass )
     {
         RouteValueDictionary attributes = new RouteValueDictionary( htmlAttributes );
         string currentController = helper.ViewContext.RouteData.Values["controller"] as string ?? "home";
         string currentAction = helper.ViewContext.RouteData.Values["action"] as string ?? "index";
         string page = string.Format( "{0}:{1}", currentController, currentAction ).ToLower();
         string thisPage = string.Format( "{0}:{1}", controller, action ).ToLower();
         attributes["class"] = (page == thisPage) ? currentClass : "";
        return helper.ActionLink( text, action, controller, new RouteValueDictionary( routeValues ), attributes );
     }
}