Hi,
I think
First:
SessionsID = HttpContext.Current.Session.SessionID.ToString();
if (Session["USERID"].ToString() != string.Empty)
{
UserName = Session["USERID"].ToString();
}
Second:
SessionsID = HttpContext.Current.Session.SessionID.ToString();
if (Session["USERID"] != null)
{
if(Session["USERID"] != string.Empty)
UserName = Session["USERID"].ToString();
}