原创 如何捕获MSComm控件的无效端口号出错（VB6.0）

Private Function funCommPortDetect(PortNumber As Integer) As Integer
    On Error Resume Next'//屏蔽错误
    MSComm0.CommPort = PortNumber'//指定端口号
    MSComm0.PortOpen = True'//打开端口
    If Err Then'//如果端口不存在产生错误
        funCommPortDetect = -1'//返回-1
    Else'//端口存在返回当前端口号
        funCommPortDetect = PortNumber
    End If
    MSComm0.PortOpen = False'//关闭打开的端口
End Function

Public Function CommPortFix() As String
    Dim intCommPortNumber As Integer, blnFirst As Boolean
    Dim strResult As String
    On Error Resume Next    '//屏蔽错误
    For intCommPortNumber = 1 To 16'//一般机器上不超过16个串口
        If funCommPortDetect(intCommPortNumber) <> -1 Then
            strResult = strResult & " " intCommPortNumber'//如果存在串口1,2,5.则结果strResult=1 2 5
        End If
    Next
    CommPortFix = strResult'//返回结果
End Function


调用的时候直接令一字符变量strString=CommPortFix()即可,得到的字符串自己可以用Split处理.如果想先预处理,返回一个数组的话可以如下定义CommPortFix()函数:

VB code

Public Function CommPortFix() As String()
Dim intCommPortNumber As Integer, blnFirst As Boolean
Dim strResult As String
On Error Resume Next '屏蔽错误
blnFirst = True
For intCommPortNumber = 1 To 16
If funCommPortDetect(intCommPortNumber) <> -1 Then
If blnFirst Then
strResult = "COM" & intCommPortNumber
blnFirst = False
Else
strResult = strResult & " " & "COM" & intCommPortNumber
End If
End If
Next
CommPortFix = Split(strResult, " ")
End Function

转自：http://topic.csdn.net/u/20080821/10/c324cb76-47c8-4410-b726-098e5b260d00.html