public static int Delete_UserSys(int id)
        {
            dbRegistrationContext context1 = new dbRegistrationContext();

            try
            {
                using (TransactionScope scope = new TransactionScope())
                {
                    USERSYS us = new USERSYS()
                    {
                        ID = id
                    };

                    context1.USERSYS.Attach(us);
                    context1.USERSYS.Remove(us);

                    try
                    {
                        context1.SaveChanges();
                        scope.Complete();
                        return(1);
                    }
                    catch (Exception)
                    {
                        return(-1);
                    }
                }
            }
            catch (Exception)
            {
                return(-1);
            }
        }
        public static int Insert_UserSys(string username, string userpass)
        {
            dbRegistrationContext context1 = new dbRegistrationContext();

            try
            {
                using (TransactionScope scope = new TransactionScope())
                {
                    int id = 0;

                    try
                    {
                        id = context1.USERSYS.Max(p => p.ID + 1);
                    }
                    catch (Exception)
                    {
                        id = 1;
                    }

                    var sha512 = new SHA512Managed();
                    var bytes  = UTF8Encoding.UTF8.GetBytes(userpass);
                    var hash   = sha512.ComputeHash(bytes);
                    var pass   = Encoding.UTF8.GetString(hash);

                    USERSYS usu = new USERSYS()
                    {
                        ID       = id,
                        USERNAME = username,
                        USERPASS = pass
                    };

                    context1.USERSYS.Add(usu);

                    try
                    {
                        context1.SaveChanges();
                        scope.Complete();
                        return(1);
                    }
                    catch (Exception)
                    {
                        return(-1);
                    }
                }
            }
            catch (Exception)
            {
                return(-1);
            }
        }