我正在研究 MVC3 剃须刀项目。我的解决方案运行正确，但现在它编译正确，但在运行时显示错误。显示以下错误，请帮我解决它。
Expression of type 'System.Web.Mvc.MvcWebRazorHostFactory' cannot be used for return type 'System.Web.WebPages.Razor.WebRazorHostFactory'
源错误：
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