How to wait for COM port receive event before sending more data in a loop

Question

I\'m working on a small component for writing and reading AT Commands using an old Sony Ericsson phone. Sending and writing to/from the phone is no problem at all, however I

Answer 1

While AsyncPro does have some solutions for this (ontriggerdata), they are event based and make code difficult to read/understand.

here is SendAndWaitForResponse with AsyncPro (like Remy suggested):

TForm1 = class(TForm)
 ...
private
    IOEvent           : THandle; // used for IO events
    IORx              : string;
    Comport           : TapdComport;
...


procedure TForm1.ComportTriggerAvail(CP: TObject; Count: Word);

var i       : integer;

begin
 for i:=1 to Count do
  IORx:=IORx+Comport.GetChar;
 SetEvent(IOEvent);
end;

function TForm1.SerialSAWR(tx : string; TimeOut : integer) : boolean;
begin
 Result := False;
 try
  IORx := ''; // your global var
  ResetEvent(IOEvent);
  Comport.PutString(tx);
  Result := WaitForSingleObject(IOEvent, TimeOut) = WAIT_OBJECT_0;
 except
  on E : Exception do
   // dosomething with exception
 end;
end;

// constructor part
IOEvent := CreateEvent(nil, True, False, nil);
// destructor part
 if IOEvent <> 0 then
  CloseHandle(IOEvent);

Best solution is to create a thread with the comport so your GUI won't be blocked. I have several applications in production with Asyncpro this way and it works like a charm...