Could not load file or assembly 'System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Getting following issue, when I compile this project.
"Could not load file or assembly 'System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified."

Solution: - 
Need to change in Webconfig file one chance after that it will work smoothly.

<compilation debug="true" targetFramework="4.5.1"  />

first time above code in webconfig file.

I just added one more attribute "optimizeCompilations="true" inside tag  and code below as.

<compilation debug="true" targetFramework="4.5.1" optimizeCompilations="true" />