主题：增加一个双精度临时列，设为2为小数 ？

Tables("月统计").Cols("单价").Move(Tables("月统计").cols.Count-1)
dt.DataCols.Add("月重量", Gettype(Double), "","月重量")
'dt.DataCols.Add("金额", Gettype(Double), "","金额")
Dim l As DataCol = dt.DataCols.Add("金额", Gettype(Double))
l.SetFormat("0.00")
 For Each r As Row In t3.Rows
    r("月重量") = Val(r("计算件重")) * r("合计")
Next
t3.Rows(t3.Rows.count-1)("月重量") = t3.Compute("Sum(月重量)")
For Each r As Row In t3.Rows
    r("金额") = val(r("月重量")) * val(r("单价"))
Next
t3.Rows(t3.Rows.count-1)("金额") = t3.Compute("Sum(金额)")

 但是算出来的金额 还不是2位小数