Could not load file or assembly 'System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral or one of its dependencies

Could not load file orassembly 'System.Web.WebPages.Razor,
 Version=3.0.0.0, Culture=neutral,PublicKeyToken=31bf3856ad364e35'
 or one of its dependencies. The locatedassembly's manifest definition
 does not match the assembly reference.(Exception from HRESULT: 0x80131040)

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

Exception Details: System.IO.FileLoadException:Could not load file or assembly 
'System.Web.WebPages.Razor, Version=3.0.0.0,Culture=neutral, PublicKeyToken=31bf3856ad364e35' 
or one of its dependencies.The located assembly's manifest definition does 
not match the assemblyreference. (Exception from HRESULT: 0x80131040)

The cause of the error due to missing the Microsoft Aspnet mvc you needed to install to the project by using Package manager console.

Install the package by using the following command in the package manager console, 

PM> Install-Package Mictrosoft.AspNet.Mvc