is there a way to know when the user perform refresh to the page using the SHDocVw.WebBrowserClass of ie using C#
There can be a better way but you can consider using Before_Navigate it should be triggered by refresh as well.
EDIT :
I've just checked the documentation apparently refresh doesn't trigger these, sorry.
I think there is no easy to way to this, you might want to try the following component :
http://code.google.com/p/csexwb2/
It's a very nice webbrowser control implementation, using C++ for tricky parts, and got a refreshbegin event that you can use.