无法加载类型“System.Web.Optimization.StyleBundle”

有时，在构建并启动我的 MVC4 Web 应用程序后，我会收到此错误。 重建后它可能会消失，也可能不消失。 发布到 Windows Azure 后我遇到了同样的问题。

有谁知道如何修复这个错误？

Server Error in '/' Application.

Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.TypeLoadException: Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 
[TypeLoadException: Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.]
   Inventarium.Web.Mobile.App.BundleConfig.RegisterBundles(BundleCollection bundles) in c:\dev\Inventarium\Inventarium.Web\Inventarium.Web.Mobile.App\App_Start\BundleConfig.cs:30
   Inventarium.Web.Mobile.App.MvcApplication.Application_Start() in c:\dev\Inventarium\Inventarium.Web\Inventarium.Web.Mobile.App\Global.asax.cs:18

[HttpException (0x80004005): Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.]
System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +4058245
System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +191
System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +352
System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +407
System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +375

 [HttpException (0x80004005): Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.]
 System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11703488
 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +141
 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4870277

根据罗曼·尼基丁的评论：

我自己发现了问题。引用有误System.Web.Optimization.dll，我的网站尝试使用旧版本。删除包然后重新添加并非每次都有帮助。

解决办法是：从所有网站完全删除旧包、引用和包配置，然后重新添加。