To update table using linq c#

  public bool update()

        {

            int res = 0;

            var query = dbcontext.taskdetails.Where(s => s.tid == 1).SingleOrDefault();

            query.name = "your updated data";

            query.amount = 500;

            res = dbcontext.SaveChanges();

            if (res > 0)

            {

                return true;

            }

            else

            {

                return false;

            }

        }