Linq Lambda 匿名方法 查找DataRow

DataRow dr = dt.Rows.Find(gv.DataKeys[e.RowIndex]["id"].ToString());
dr["flag"] = "0";

IEnumerable<DataRow> q = from dr in dt.AsEnumerable()
where dr.Field<int>("id").ToString() == gv.DataKeys[i]["id"].ToString()
select dr;
foreach (DataRow dr in q)
dr["flag"] = "0";

IEnumerable<DataRow> q = dt.AsEnumerable().Where<DataRow>(r => (r.Field<int>("id").ToString() == gv.DataKeys[e.RowIndex]["id"].ToString()));
foreach (DataRow dr in q)
dr["flag"] = "0";

IEnumerable<DataRow> q = dt.AsEnumerable().Where<DataRow>(delegate(DataRow r) { return r["id"].ToString() == gv.DataKeys[i]["id"].ToString(); });
foreach (DataRow dr in q)
dr["flag"] = "0";