in MVC3 razor we found that their is no way to watch the design in Visual studio as well we can see aspx file by going to design mode.

their is a little trick to solve this issue

first is that if you have Expression web or Vs 2008 then open the file on them how see here

in expression web 4 you need to add the extension .cshtml and open them as html as we open other.

in Visual studio 2008 you need to add the extension .cshtml and set them open as html.

well their is no big trouble if design not worked. but in some case when you need to get this issue solved this need to be work

for configuration do this:

Expression Web 4 > tools > application options > configure editor > click on new extension icon show in exact left

put the cshtml in the window they show you and choose expression web [open as html]

after that you can see the design in expression web.

by default Expression web not have cshtml as known extension so you need to do that to add them because without it they never handle cshtml file and refer them to Visual studio. after setting this you  EW4 open the cshtml file as html and show you design in design mode.

in Visual studio 2008 you can use same trick to solve this issue just follow this step >

options > text editors > file extension put cshtml in textbox and set the option html editor from dropdown and click on add and ok this will open your cshtml file as html.