关于VB，mscomm控件和西门子plc通行的问题

[soller_T]

Private Sub MSComm1_OnComm()
If Command2.Caption = "停止接受" Then
Select Case CommEvent
Case comEvReceive
temp = MSComm1.Input
ReDim Preserve temp(UBound(temp)) As Byte
For i = LBound(temp) To UBound(temp)
Text2 = Text2 & str$(temp(i)) & " "
Next i
End Select

End If

End Sub

usb/ppi电缆的发送信号和接受信号都亮起，但是没有显示到text2上，是代码有问题还是其他什么原因，希望各位提供帮助，不甚感激~

[熊孩子开学喽]

首先你得知道temp到底有没有收到数据

[of123]

If Command2.Caption = "停止接收" Then '首先检查这里，字符串是否与命令按钮显示的相同
    Select Case CommEvent
        Case comEvReceive
            temp = MSComm1.Input
            If MSComm1.InputMode=comInputModeText Then
                Text2 = StrConv(temp, vbUnicode)
            Else
                For i = LBound(temp) To UBound(temp)
                    Text2 = Text2 & IIf(Text2 = "", "", " ") & Right("0" & Hex(temp(i)), 2)
                Next i
            End If
    End Select
End If