ASP.Net go back to previous page after logged in ...

First of all Save current page in a Session Variable...........

Session["previous"] = Request.UrlReferrer.ToString();  

after that redirect to login page

Response.Redirect("~/login.aspx");

then write down this code after login code to got redirect to previous page...

Response.Redirect(Session["previous"].toString());

Page will got back redirect to previous page........