主题：保质期（含小时）计算

Select Case e.DataCol.Name
    Case "到期日期"
        Dim dr As DataRow = e.DataRow
        If dr.IsNull("到期日期")  Then
            dr("保质时间") = Nothing
        Else
            Dim tp As TimeSpan = dr("到期日期")  - Date.Now
            dr("保质时间") = tp.Days & ":" & tp.Hours
        End If
End Select