Linq对DataTable或者集合的排序，Where筛选，分组，统计总数sum等操作

//对集合进行筛选，排序，分组

var query = (from x in dsResult.Tables[0].AsEnumerable()
Where DataTrans.CBoolean(x[" IsChecked "]) == true
Group x By new
{
no = x.Field<string>(" NO "),
ptno = x.Field<string>(" PTNO "),
ver = x.Field<int>(" VER "),
kd = x.Field<string>(" KD "),
que_da = Convert.ToDateTime(x.Field<DateTime>(" QUE_DA ").ToString(" yyyy/MM/dd "))
} into g
OrderBy g.Key.no,g.Key.ptno,g.Key.ver,g.Key.kd,g.Key.que_da
select new
{
qty = g.Sum(x => Convert.ToInt32(x[" QUE_QTY "])),
stock=g.Sum(x=>Convert.ToInt32(x[" STOCK "])),
no=g.Key.no ,
ptno=g.Key.ptno,
ver=g.Key.ver,
kd=g.Key.kd,
que_da=g.Key.que_da
});

//统计一列的总数

var dtUnCheckNum = objFinanceCheckDB.UnCheckNum_Get(strReportDate1);
var queryTotal = (from DataRow row in dtUnCheckNum.Rows
select new { qsum = row["UnCheckNum"] }).Sum(a => Convert.ToInt32(a.qsum));
if (queryTotal == 0)
{
lblWrongNum.Text = "0";
}

//简单按条件过滤

var records = dt.AsEnumerable().Where(a => Convert.ToInt32(a[0]) < 1000);
DataView rsl = records.AsDataView();