在C＃中发现串行端口

Question

I'm writing an application that communicates by sending bytes to the USB port. I'd like to allow the user to choose the port and to do that, I use SerialPort.GetPortNames() . Unfortunately, it returns an empty array. The method supposedly reads the registry for data (HKEY_LOCAL_MACHINE\\HARDWARE\\DEVICEMAP\\SERIALCOMM), but the SERIALCOMM directory is missing. When I run the program on Linux, it lists my four USB ports, as expected. How can I fix the registry/discover the ports in a different way?

Answer 1

You could use Management Objects to query available COM ports. The interesting tables are:

• MSSerial_PortName in root\\WMI
• MSWmi_PnPInstanceNames in root\\WMI
• Win32_PnPEntity in root\\CIMV2

You can explore these namespaces in the WMI Code Creator , and generate VBScript/VB/C# code.

Answer 2

The SerialPort.GetPortNames() are the correct method to discover serial ports. But if you are using Windows 7, I think it could be issues with permissions on the registry keys this method lists. I found a post which describe this problem at Microsoft.com .

Answer 3

SerialPort.GetPortNames() returns the list of COM ports install on the machine, not USB ports. I don't think Windows will provide you with a list of USB ports, only USB devices that are available.

Despite the name "Universal Serial Bus", they are not "Serial Ports" in the convential meaning.