declare a serial port

I am converting an application from VB6 to .NET

The VB6 code was:
Sub InitComPort(ComPort As Control, PortNum As Integer)
    ' -------------------------------
    ' setups the commport
    ' ------------------------------

    On Local Error Resume Next
    If ComPort.PortOpen = True Then
        ComPort.PortOpen = False
    End If
    ComPort.CommPort = PortNum
   
    ComPort.Settings = "9600,N,8,1"
   
    ComPort.PortOpen = True
   
    ComPort.RThreshold = 0
   
    SendingCmd = False
   
End Sub

How does the ComPort get defined in VB.NET.
Thanks,