为什么串口有的关键字在2008上不认识？

Question

Select Case tongxun1.CommEvent
            Case comEvReceive
                jieshou = tongxun1.Input
                shuju(0) = jieshou
                If shuju(0) = 255 Then
                    tongxun1.RThreshold = 0
                    For a = 1 To 9
                        jieshou = tongxun1.Input
                        shuju(a) = jieshou
                    Next a
                    tongxun1.RThreshold = 10
                End If
        End Select

为什么在写的时候，comEvReceive会提示未定义，这在VB6.0上是CommEven的返回值啊，还有好多串口事件不认识，关于CommEvent的事件都不认识，很头疼！！！求帮助