主题：请版主指教

If e.DataCol.Name = "录入日期" Then

    If e.DataRow.IsNull("录入日期") Then

        e.DataRow("产品编号") = Nothing

    Else

        Dim d As Date = e.DataRow("录入日期")

        Dim y As Integer = d.Year

        Dim m As Integer = d.Month

        Dim Days As Integer = Date.DaysInMonth(y,m)

        Dim fd As Date = New Date(y,m,1)

        Dim ld As Date = New Date(y,m,Days)

        Dim bh As String = e.datarow("产品类型") & Format(d,"MMdd")

        Dim drs As List(of DataRow) = e.DataTable.Select("录入日期 >= #" & fd & "# And 录入日期 <= #" & ld & "#")

        For i As Integer = 0 To drs.Count - 1

            drs(i)("产品编号")  = bh & format(i+1,"000")

        Next

    End If

End If

现成的例子,自己修改一下吧.