Select Case e.DataCol.Name Case "第一列","第二列" For Each dr As DataRow In e.DataTable.Select("[_SortKey] >= " & e.DataRow("_SortKey")) If dr.IsNull("第一列") OrElse dr.IsNull("第二列") Then dr("余额累计") = Nothing Else Dim Val1 As Double = e.DataTable.Compute("Sum(第一列)","[_SortKey] <= " & dr("_SortKey")) Dim Val2 As Double = e.DataTable.Compute("Sum(第二列)","[_SortKey] <= " & dr("_SortKey")) dr("余额累计") = Val1 - Val2 End If Next End Select