xcopy /e/r/y $(ProjectDir)Areas\Admin\Views 
$(SolutionDir)Secom.Emx.WebApp\Areas\Admin\Views

using System.Web.Mvc;

namespace Secom.Emx.WebApp
{
 public class AdminAreaRegistration : AreaRegistration 
 {
  public override string AreaName 
  {
   get 
   {
    return "Admin";
   }
  }

  public override void RegisterArea(AreaRegistrationContext context) 
  {
   context.MapRoute(
    "Admin_default",
    "Admin/{controller}/{action}/{id}",
    new { action = "Index", id = UrlParameter.Optional },
    namespaces:new string[1] { "Secom.Emx.Admin.Areas.Admin.Controllers" }
   );
  }
 }
}

using System.Web.Mvc;

namespace Secom.Emx.WebApp
{
 public class HistoryAreaRegistration : AreaRegistration 
 {
  public override string AreaName 
  {
   get 
   {
    return "History";
   }
  }

  public override void RegisterArea(AreaRegistrationContext context) 
  {
   context.MapRoute(
    "History_default",
    "History/{controller}/{action}/{id}",
    new { action = "Index", id = UrlParameter.Optional },
    namespaces:new string[1] { "Secom.Emx.History.Areas.History.Controllers" }
   );
  }
 }
}

public RazorViewEngine(IViewPageActivator viewPageActivator) 
  : base(viewPageActivator) 
 { 
  AreaViewLocationFormats = new[] 
  { 
   "~/Areas/{2}/Views/{1}/{0}.cshtml", 
   "~/Areas/{2}/Views/{1}/{0}.vbhtml", 
   "~/Areas/{2}/Views/Shared/{0}.cshtml", 
   "~/Areas/{2}/Views/Shared/{0}.vbhtml" 
  }; 
  AreaMasterLocationFormats = new[] 
  { 
   "~/Areas/{2}/Views/{1}/{0}.cshtml", 
   "~/Areas/{2}/Views/{1}/{0}.vbhtml", 
   "~/Areas/{2}/Views/Shared/{0}.cshtml", 
   "~/Areas/{2}/Views/Shared/{0}.vbhtml" 
  }; 
  AreaPartialViewLocationFormats = new[] 
  { 
   "~/Areas/{2}/Views/{1}/{0}.cshtml", 
   "~/Areas/{2}/Views/{1}/{0}.vbhtml", 
   "~/Areas/{2}/Views/Shared/{0}.cshtml", 
   "~/Areas/{2}/Views/Shared/{0}.vbhtml" 
  }; 
  
  ViewLocationFormats = new[] 
  { 
   "~/Views/{1}/{0}.cshtml", 
   "~/Views/{1}/{0}.vbhtml", 
   "~/Views/Shared/{0}.cshtml", 
   "~/Views/Shared/{0}.vbhtml" 
  }; 
  MasterLocationFormats = new[] 
  { 
   "~/Views/{1}/{0}.cshtml", 
   "~/Views/{1}/{0}.vbhtml", 
   "~/Views/Shared/{0}.cshtml", 
   "~/Views/Shared/{0}.vbhtml" 
  }; 
  PartialViewLocationFormats = new[] 
  { 
   "~/Views/{1}/{0}.cshtml", 
   "~/Views/{1}/{0}.vbhtml", 
   "~/Views/Shared/{0}.cshtml", 
   "~/Views/Shared/{0}.vbhtml" 
  }; 
  
  FileExtensions = new[] 
  { 
   "cshtml", 
   "vbhtml", 
  }; 
 }

using System.Web.Mvc;

namespace Secom.Emx.WebApp.Helper
{
 public class CustomRazorViewEngine : RazorViewEngine
 {
  public CustomRazorViewEngine(string theme)
  {
   if (!string.IsNullOrEmpty(theme))
   {
    AreaViewLocationFormats = new[]
    {
      //themes
      "~/themes/"+theme+"/views/Areas/{2}/{1}/{0}.cshtml",
      "~/themes/"+theme+"/Shared/{0}.cshtml"

  "~/Areas/{2}/Views/{1}/{0}.cshtml",
  "~/Areas/{2}/Views/Shared/{0}.cshtml"
 };
    AreaMasterLocationFormats = new[]
    {
        //themes
    "~/themes/"+theme+"/views/Areas/{2}/{1}/{0}.cshtml",
    "~/themes/"+theme+"/views/Areas/{2}/Shared/{0}.cshtml",
    "~/themes/"+theme+"/views/Shared/{0}.cshtml",

  "~/Areas/{2}/Views/{1}/{0}.cshtml",
  "~/Areas/{2}/Views/Shared/{0}.cshtml"
 };
    AreaPartialViewLocationFormats = new[]
    {
       //themes
   "~/themes/"+theme+"/views/Shared/{0}.cshtml",

  "~/Areas/{2}/Views/{1}/{0}.cshtml",
  "~/Areas/{2}/Views/Shared/{0}.cshtml"
 };

    ViewLocationFormats = new[]
    {
       //themes
   "~/themes/"+theme+"/views/{1}/{0}.cshtml",

  "~/Views/{1}/{0}.cshtml",
  "~/Views/Shared/{0}.cshtml"
 };
    MasterLocationFormats = new[]
    {
       //themes
   "~/themes/"+theme+"/views/Shared/{0}.cshtml",

  "~/Views/{1}/{0}.cshtml",
  "~/Views/Shared/{0}.cshtml"
 };
    PartialViewLocationFormats = new[]
    {
       //themes
  "~/themes/"+theme+"/views/Shared/{0}.cshtml",

  "~/Views/{1}/{0}.cshtml",
  "~/Views/Shared/{0}.cshtml"
 };

    FileExtensions = new[]{"cshtml"};
   }

  }
 }
}

<div class="btn-group">
     <button type="button" class="btn btn-circle btn-outline red dropdown-toggle" data-toggle="dropdown">
      <i class="fa fa-plus"></i> 
      <span class="hidden-sm hidden-xs">切换主题 </span> 
      <i class="fa fa-angle-down"></i>
     </button>
     <ul class="dropdown-menu" role="menu">
      <li>
       <a href="javascript:setTheme('default')">
        <i class="icon-docs"></i> 默认主题
       </a>
      </li>
      <li>
       <a href="javascript:setTheme('Blue')">
        <i class="icon-tag"></i> 蓝色主题
       </a>
      </li>
     </ul>
    </div>
  <script type="text/javascript">
   function setTheme(themeName)
   {
    window.location.href = "/Home/SetTheme?themeName=" + themeName + "&href=" + window.location.href;
   }
</script>

using System;
using System.Web.Mvc;
using Secom.Emx.WebApp.Helper;
using System.Web;
using Secom.Emx.Common.Controllers;

namespace Secom.Emx.WebApp.Controllers
{
 public class HomeController : BaseController
 {
  string themeCookieName = "Theme";
  public ActionResult Index()
  {
   ViewData["Menu"] = GetMenus();
   return View();
  }
  public ActionResult SetTheme(string themeName,string href)
  {
   if (!string.IsNullOrEmpty(themeName))
   {
    Response.Cookies.Set(new HttpCookie(themeCookieName, themeName) { Expires = DateTime.Now.AddYears(1) });
   }
   else
   {
    themeName = Request.Cookies[themeCookieName].Value ?? "".Trim();
   }
   Utils.ResetRazorViewEngine(themeName);
   return string.IsNullOrEmpty(href)? Redirect("~/Home/Index"):Redirect(href);
  }
  public ActionResult Login()
  {
   string themeName = Request.Cookies[themeCookieName].Value ?? "".Trim();
   if (!string.IsNullOrEmpty(themeName))
   {
    Utils.ResetRazorViewEngine(themeName);
   }
   return View();
  }
 }
}

using System.Configuration;
using System.Web.Mvc;

namespace Secom.Emx.WebApp.Helper
{
 public class Utils
 {
  private static string _themeName;

  public static string ThemeName
  {
   get
   {
    if (!string.IsNullOrEmpty(_themeName))
    {
     return _themeName;
    }
    //模板风格
    _themeName =string.IsNullOrEmpty(ConfigurationManager.AppSettings["Theme"])? "" : ConfigurationManager.AppSettings["Theme"];
    return _themeName;
   }
  }
  public static void ResetRazorViewEngine(string themeName)
  {
   themeName = string.IsNullOrEmpty(themeName) ? Utils.ThemeName : themeName;
   if (!string.IsNullOrEmpty(themeName))
   {
    ViewEngines.Engines.Clear();
    ViewEngines.Engines.Add(new CustomRazorViewEngine(themeName));
   }
  }
 }
}