Public Shared Function GetFreeUsablePorts() As String()
        Dim TestPort As SerialPort = New SerialPort, MyPorts As String()
        Dim ports() As String, port As String, i As Integer = 0
 
        ports = IO.Ports.SerialPort.GetPortNames()          'Ports des Rechners 
        ' ermitteln
        ReDim MyPorts(ports.Length - 1)
        For Each port In ports
            Try
                With TestPort
                    .PortName = port                        'Com 1, 2, ..., n
                    .ReadTimeout = 500                      'ReadTimeout in ms
                    .Open()                                 'Versuchen zu öffnen
                End With
 
            Catch ex As Exception                           'Fehlschlag
 
            Finally                                         
                If TestPort.IsOpen = True Then
                    MyPorts(i) = port
                End If
 
                TestPort.Close()
 
            End Try
            I += 1
        Next port
 
        Return MyPorts
 
    End Function

Public Shared Function GetPortStatus() As ????
        Dim TestPort As SerialPort = New SerialPort, Status as ????
        Dim ports() As String, port As String, i As Integer = 0
 
        ports = IO.Ports.SerialPort.GetPortNames()          'Ports des Rechners 
        ' ermitteln
 
        For Each port In ports
            Try
                With TestPort
                    .PortName = port                        'Com 1, 2, ..., n
                    .ReadTimeout = 500                      'ReadTimeout in ms
                    .Open()                                 'Versuchen zu öffnen
                End With
 
            Catch ex As Exception                           'Fehlschlag
 
            Finally 
 
                Status=port   'Namen des Ports Übergeben
 
                If TestPort.IsOpen = True Then  'Status des Ports Übergeben
                    Status = True
                Else
                    Status = False
                End If
 
                TestPort.Close()
            End Try
            i += 1
        Next port
 
        Return Status  'Typ zurückgeben
 
    End Function
 
End Class

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