哦，想复杂了。

Select e.DataCol.Name
    Case "进库日期","发票号码"
        If e.DataRow.IsNull("进库日期") OrElse e.DataRow.IsNull("发票号码") Then
            e.DataRow("托盘编号") = Nothing
        Else
            Dim d As Date = e.DataRow("进库日期")
            Dim y As Integer = d.Year
            Dim m As Integer = d.Month
            Dim bh As String = "TS-" & Format(d,"yyMMdd") & "-"
            Dim fd As Date = New Date(y,m,1) \'获得该月的第一天
            Dim ld As Date = fd.AddMonths(1)
            Dim max As String
            Dim idx As Integer
            Dim flt As String
            flt = "进库日期 >= #" & fd & "# And 进库日期 < #" & ld & "# And 发票号码 = \'" & e.DataRow("发票号码") & "\' And [_Identify] <> " & e.DataRow("_Identify")
            max = e.DataTable.Compute("Max(托盘编号)",flt) \'取得该月的相同发票号码的最大托盘编号
            msgbox(max)
            If max > "" Then \'如果存在最大托盘编号
                idx = CInt(max.Substring(bh.length,4)) + 1 \'获得最大托盘编号的后四位顺序号,并加1
            Else
                idx = 1 \'否则顺序号等于1
            End If
            e.DataRow("托盘编号") = bh & Format(idx,"0000") & "-" & e.DataRow("发票号码")
           
        End If
End Select