SerialPort.GetPortNames() not returning correct result

Question

I'm developing small demo application for Windows Mobile 6.1 to get the list of all serial ports and the Bluetooth devices configured on them. I'm facing some weird problem.

1) I can see total 10 COM ports when I go to Settings->Connections->Bluetooth->COM POrts. But when I use SerialPort.GetPortNames() to get all the ports, it shows 9 ports i.e. one port less. The last port i.e. COM09 is not returned in the result set.

2) Then I removed one of the paired devices configured on one of the COM ports (COM08) and SerialPort.GetPortNames() returned the result set WITHOUT the COM08 port.

3) I further tried to know which COM ports are still unused. When i tried to create "New Outgoing Port" manually on one of the 'unused' (as per my program) port, it gives a message saying "COM port cannot be created"!

Could someone tell me the reason and guide me further to resolve the issue?

Answer 1

The Bluetootch driver is probably modifying the registry key where the Drivers are and GetPortNames is probably looking through that key.

Take a look at both HKLM\Drivers\BuiltIn and HKLM\Drivers\Active with the remove registry editor and see what's happening. You can likely write your own parser that looks at these values for what you are after.