I'm sorry - wrong code :-(

That should be ocommform.comminput.input to read the port. Here is the basic definition that uses a form class property "inbuffer" to hold the data. It could just as easily be a property of your control subclass.

DEFINE CLASS incomm AS CUSTOM
  IMPLEMENTS dmscommevents IN mscomm32.ocx
  PROCEDURE dmscommevents_oncomm
    WITH ocommform
      IF .comminput.commevent = 2
        .inbuffer = .inbuffer + .comminput.INPUT
    ENDWITH
  ENDPROC
ENDDEFINE