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Option Explicit
Dim a As Integer
Private Sub Command1_Click()
On Error GoTo uerror
For a = 1 To 16
MSComm1.CommPort = a
MSComm1.PortOpen = True
If MSComm1.PortOpen = True Then
Print "可用Com号= "; a
MSComm1.PortOpen = False
Else
End If
Next
Exit Sub
uerror:
Print "出错或占用Com号= "; a
Resume Next
End Sub
Private Sub Form_Load()
On Error GoTo userr
MSComm1.PortOpen = True
'Print MSComm1.PortOpen
Exit Sub
userr:
If MSComm1.PortOpen = True Then
MSComm1.PortOpen = False
End If
'Print MSComm1.PortOpen
Resume
End Sub