参考:http://www.foxtable.com/webhelp/scr/1572.htm
Select Case e.DataCol.Name
Case "收入","支出"
Dim Val1 As Double = e.DataTable.Compute("Sum(收入)","[_SortKey] < " & e.DataRow("_SortKey"))
Dim Val2 As Double = e.DataTable.Compute("Sum(支出)","[_SortKey] < " & e.DataRow("_SortKey"))
e.DataRow("余额") = Val1 - Val2
End Select