if(!string.IsNullOrEmpty((string)Session["username"]) && (string)Session["username"] == "Anton")
 {
   btnNew.Visible = true;
 }
 else
 {
   btnNew.Visible = false;
 }
solved If Username == Anton, then do something
 
if(!string.IsNullOrEmpty((string)Session["username"]) && (string)Session["username"] == "Anton")
 {
   btnNew.Visible = true;
 }
 else
 {
   btnNew.Visible = false;
 }
solved If Username == Anton, then do something