var allrows = db.works.Where(x => x.Status == 100).OrderByDescending(x => x.ID_Work).ToPagedList(pageNumber, pageSize);

var allrows = db.works.Where(x => x.Status == 100);
     if(!String.IsNullOrEmpty(Code_Work))
      {
       allrows= allrows.Where(x => x.Code_Work.Contains(Code_Work));
       ViewBag.CurrentCode_Work = Code_Work;
      }
var pagedrows = allrows.OrderByDescending(x => x.ID_Work).ToPagedList(pageNumber, pageSize);