摘要：
var linqbitem = from wip in dt_onwip.AsEnumerable() join bitem in dt_cos_bitem.AsEnumerable() on wip.Field<string>("item_no").Trim() equals bitem.Field<string>("item_no").Trim() into s from t in s.DefaultIfEmpty() select new { item_no = wip.Field<string>("i 阅读全文