主题：同表，根据双列（品名和型号规格两列）累计数量

的代码如下：

datacolchanged

Select Case e.DataCol.Name
    Case "品名", "数量"
        Dim drs As List(of DataRow)
        Dim Filter As String
        Filter = "[_SortKey] >= " & e.DataRow("_SortKey") & " And [品名] = '" & e.DataRow("品名") & "'"
        drs = e.DataTable.Select(Filter)
        For Each dr As DataRow In drs
            Filter = "[_SortKey] <= " & dr("_SortKey") & " And [品名] = '" & dr("品名") & "'"
            Dim Val1 As Double = e.DataTable.Compute("Sum(数量)",Filter)
            dr("本品名型号规格累计") = Val1
        Next
        If e.DataCol.Name = "品名" AndAlso e.OldValue IsNot Nothing AndAlso e.OldValue <> e.NewValue Then
            Filter = "[_SortKey] > " & e.DataRow("_SortKey") & " And [品名] = '" & e.OldValue & "'"
            drs = e.DataTable.Select(Filter)
            For Each dr As DataRow In drs
                Filter = "[_SortKey] <= " & dr("_SortKey") & " And [品名] = '" & dr("品名") & "'"
                Dim Val1 As Double = e.DataTable.Compute("Sum(数量)",Filter)
                dr("本品名型号规格累计") = Val1
            Next
        End If
End Select

请问：根据品名和型号规格累计数量（即同品名和型号数量累加）的代码如何修改？谢谢！

要求的效果如下表：

行，谢谢了！