检查COM端口的最快方法

Question

I need to check for available COM ports in my application:

I created two ways to do this.

Method 1:

public List<string> GetAllPortsForeach()
{
     var allPorts = new List<string>();
     foreach (String portName in System.IO.Ports.SerialPort.GetPortNames())
     {
           allPorts.Add(portName);
     }
     return allPorts;
} 

Method 2:

public List<string> GetAllPortsForLoop()
{
      var allPorts = new List<string>();
       for (int i = 1; i <= 16; i++)
       {
           string comPortName = "COM" + Convert.ToString(i);
           SerialPort sp = new SerialPort(comPortName);
           try
           {
               sp.Open();
               allPorts.Add(comPortName);               
               sp.Close();
            }
            catch
            {
            }
        }
        return allPorts;
}

Which is the fastest? Which should I use and why?

Answer 1

The 1st one. It reads all available port names from registry. To be more precise, it is just enough to use SerialPort.GetPortNames , if you're not planning to add any custom port name to the list.

The 2nd one:

• limited by port number (port name can be "COM20", but the total numbers of ports in the system will be, eg, 4)
• exception-based (this is ugly and slower).