string _keyWord = textBox1.Text;


var pred = PredicateBuilder.False<Shp_bat>();

 /// foreach (string keyword in keywords)
 /// {
 ///   string temp = keyword;
 ///   predicate = predicate.Or (p => p.Description.Contains (temp));
 /// }

    pred= pred.Or(x=>x.nbr.Contains(_keyWord));
    pred= pred.Or(x=>x.sale_nbr.Contains(_keyWord));
    pred= pred.Or(x=>x.cus_nbr.Contains(_keyWord));


var q = _context.Shp_bah.AsExpandable().Where(pred);

等同於_context.Shp_bah.Where(o => x.nbr == _keyWord && x.sale_nbr == _keyWord)