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    <p>Another option is use the WMI Events, on this case using the <code>__InstanceCreationEvent</code> Event and the <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/aa394353%28v=vs.85%29.aspx" rel="noreferrer"><code>Win32_PnPEntity</code></a> WMI class you can filter the serial ports added using the <a href="http://msdn.microsoft.com/en-us/library/windows/hardware/ff553426%28v=vs.85%29.aspx" rel="noreferrer"><code>{4d36e978-e325-11ce-bfc1-08002be10318}</code></a> class GUID, writting a WQL sentence like so </p> <pre><code>Select * From __InstanceCreationEvent Within 1 Where TargetInstance ISA "Win32_PnPEntity" AND TargetInstance.ClassGuid="{4d36e978-e325-11ce-bfc1-08002be10318}" </code></pre> <p>Try this sample</p> <pre><code>{$APPTYPE CONSOLE} {$R *.res} uses Windows, {$IF CompilerVersion &gt; 18.5} Forms, {$IFEND} SysUtils, ActiveX, ComObj, WbemScripting_TLB; type TWmiAsyncEvent = class private FWQL : string; FSink : TSWbemSink; FLocator : ISWbemLocator; FServices : ISWbemServices; procedure EventReceived(ASender: TObject; const objWbemObject: ISWbemObject; const objWbemAsyncContext: ISWbemNamedValueSet); public procedure Start; constructor Create; Destructor Destroy;override; end; //Detect when a key was pressed in the console window function KeyPressed:Boolean; var lpNumberOfEvents : DWORD; lpBuffer : TInputRecord; lpNumberOfEventsRead : DWORD; nStdHandle : THandle; begin Result:=false; nStdHandle := GetStdHandle(STD_INPUT_HANDLE); lpNumberOfEvents:=0; GetNumberOfConsoleInputEvents(nStdHandle,lpNumberOfEvents); if lpNumberOfEvents&lt;&gt; 0 then begin PeekConsoleInput(nStdHandle,lpBuffer,1,lpNumberOfEventsRead); if lpNumberOfEventsRead &lt;&gt; 0 then begin if lpBuffer.EventType = KEY_EVENT then begin if lpBuffer.Event.KeyEvent.bKeyDown then Result:=true else FlushConsoleInputBuffer(nStdHandle); end else FlushConsoleInputBuffer(nStdHandle); end; end; end; { TWmiAsyncEvent } constructor TWmiAsyncEvent.Create; const strServer ='.'; strNamespace ='root\CIMV2'; strUser =''; strPassword =''; begin inherited Create; CoInitializeEx(nil, COINIT_MULTITHREADED); FLocator := CoSWbemLocator.Create; FServices := FLocator.ConnectServer(strServer, strNamespace, strUser, strPassword, '', '', wbemConnectFlagUseMaxWait, nil); FSink := TSWbemSink.Create(nil); FSink.OnObjectReady := EventReceived; FWQL:='Select * From __InstanceCreationEvent Within 1 '+ 'Where TargetInstance ISA "Win32_PnPEntity" AND TargetInstance.ClassGuid="{4d36e978-e325-11ce-bfc1-08002be10318}" '; end; destructor TWmiAsyncEvent.Destroy; begin if FSink&lt;&gt;nil then FSink.Cancel; FLocator :=nil; FServices :=nil; FSink :=nil; CoUninitialize; inherited; end; procedure TWmiAsyncEvent.EventReceived(ASender: TObject; const objWbemObject: ISWbemObject; const objWbemAsyncContext: ISWbemNamedValueSet); var PropVal: OLEVariant; begin PropVal := objWbemObject; Writeln(Format('TargetInstance.ClassGuid : %s ',[String(PropVal.TargetInstance.ClassGuid)])); Writeln(Format('TargetInstance.Description : %s ',[String(PropVal.TargetInstance.Description)])); Writeln(Format('TargetInstance.Name : %s ',[String(PropVal.TargetInstance.Name)])); Writeln(Format('TargetInstance.PNPDeviceID : %s ',[String(PropVal.TargetInstance.PNPDeviceID)])); Writeln(Format('TargetInstance.Status : %s ',[String(PropVal.TargetInstance.Status)])); end; procedure TWmiAsyncEvent.Start; begin Writeln('Listening events...Press Any key to exit'); FServices.ExecNotificationQueryAsync(FSink.DefaultInterface,FWQL,'WQL', 0, nil, nil); end; var AsyncEvent : TWmiAsyncEvent; begin try AsyncEvent:=TWmiAsyncEvent.Create; try AsyncEvent.Start; //The next loop is only necessary in this sample console sample app //In VCL forms Apps you don't need use a loop while not KeyPressed do begin {$IF CompilerVersion &gt; 18.5} Sleep(100); Application.ProcessMessages; {$IFEND} end; finally AsyncEvent.Free; end; except on E:EOleException do Writeln(Format('EOleException %s %x', [E.Message,E.ErrorCode])); on E:Exception do Writeln(E.Classname, ':', E.Message); end; end. </code></pre>
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