I am following this article on RazorGenerator and it say\'s that I must add references to:
System.Web.Helpers.dllSystem.Web.WebPag
I had the same problem , first I couldn't find those dlls in the list of .NET components . but later I figured it out that the solution is :
1- first I changed target framework from .NET framework 4 client profile to .NET framework 4.
2- then scroll down the list of .NET components , pass first list of system.web... , scroll down , and find the second list of system.web... at the bottom , they're there .
I hope this could help others