manage login session

after verify user is valid and then add

session["user"]=txtuname.text;

here we create the user session with textbox of name of user.

after login and redirect successful at the master page in page_load event

if(Session["user"]==""||session["user"]==null)
{
      btn_logut.visible=false;
}
else
{
   btn_logut.visible=true;
}