C# 计算

DataTable dt = new DataTable();
var sum1 = dt.Compute("SUM(Volume)", "");

DataRow[] drList = dt.Select("Name=‘AAA‘");
var sum2 = drList.Sum(x => x.Field<decimal>("Volume"));

var tJlbList = new List<TJlb_Mod>();
var sum3 = tJlbList.Sum(o => o.FBcfs);

var sum4 = tJlbList.SelectMany(x => x.TJlb_P_Items).Sum(o => o.FBcfs);