Queryable..::.Take<(Of<(TSource>)>) 泛型方法
从序列的开头返回指定数量的连续元素。
var rcs = (from r in db.Rains where r.RTU_ID == e.CoverdItem.PointName & r.Ch == 1 orderby r.time descending select r).Take(288); int rc1Last = rcs.AsEnumerable().Last().RC; int rc1First = rcs.AsEnumerable().First().RC;