Reputation: 369

WMI not working after upgrading to Windows 10

I had been using the code below for a console application in Visual Studio on Windows 8 to return the description and device ID of connected serial devices. I was using a modified version of this in an application I'm creating to automatically detect the COM port of an Arduino. It no longer returns anything since I've done a fresh install with Windows 10. I have a USB to serial AVR programmer that still shows up using this code however. I checked the registry and the Arduino is listed in SERIALCOMM, the Arduino is showing as 'USB Serial Port (COM6)' under 'Ports (COM & LPT)' in Device Manager and I can program the Arduino using the Arduino software. I have no idea why it isn't working any more.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Management;
using System.IO.Ports;
using System.Diagnostics;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main() 
        {


            ManagementScope connectionScope = new ManagementScope();
            SelectQuery serialQuery = new SelectQuery("SELECT * FROM Win32_SerialPort");
            ManagementObjectSearcher searcher = new ManagementObjectSearcher(connectionScope, serialQuery);

            try
            {
                foreach (ManagementObject item in searcher.Get())
                {
                    string desc = item["Description"].ToString();
                    string deviceId = item["DeviceID"].ToString();

                    Console.WriteLine(desc);
                    Console.WriteLine(deviceId);
                }
            }
            catch (ManagementException e)
            {
                Console.WriteLine(e.Message);
            }

            Console.ReadKey();
        }
    }
}

It might also be relevant that while trying to find a solution I found the following implementation to find port names using MSSerial_PortName and I got an Access Denied error.

using System;
using System.Management;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main() 
        {
            try
            {
                ManagementObjectSearcher MOSearcher = new ManagementObjectSearcher("root\\WMI", "SELECT * FROM MSSerial_PortName");

                foreach (ManagementObject MOject in MOSearcher.Get())
                {
                    Console.WriteLine(MOject["PortName"]); 
                }
            }
            catch (ManagementException me)
            {
                Console.WriteLine("An error occurred while querying for WMI data: " + me.Message);
            }
            Console.ReadKey();
        }
    }
}

Upvotes: 4

Answers (3)

Wouter Schut

Reputation: 927

A bit smaller solution than Juderb

    public static List<string> FindComPorts()
    {
        using (var searcher = new ManagementObjectSearcher("SELECT * FROM Win32_PnPEntity WHERE ConfigManagerErrorCode = 0"))
        {
            return searcher.Get().OfType<ManagementBaseObject>()
                .Select(port => Regex.Match(port["Caption"].ToString(), @"\((COM\d*)\)"))
                .Where(match => match.Groups.Count >= 2)
                .Select(match => match.Groups[1].Value).ToList();
        }
    }

Tested this on win7 + win10. Btw, you can add extra search criteria to the regex if you want (or just add a new Where clause)

Upvotes: 1

Juderb

Reputation: 735

Ok, I think I see the issue now (I will add a new answer, but won't replace the old in case someone finds the information useful).

Win32_SerialPort only detects hardware serial ports (e.g. RS232). Win32_PnPEntity identifies plug-and-play devices including hardware and virtual serial ports (e.g. COM port created by the FTDI driver).

To use Win32_PnPEntity to identify a driver requires a little extra work. The following code identifies all COM ports on the system and produces a list of said ports. From this list, you may identify the appropriate COM port number to create your SerialPort object.

// Class to contain the port info.
public class PortInfo
{
  public string Name;
  public string Description;
}

// Method to prepare the WMI query connection options.
public static ConnectionOptions PrepareOptions ( )
{
  ConnectionOptions options = new ConnectionOptions ( );
  options . Impersonation = ImpersonationLevel . Impersonate;
  options . Authentication = AuthenticationLevel . Default;
  options . EnablePrivileges = true;
  return options;
}

// Method to prepare WMI query management scope.
public static ManagementScope PrepareScope ( string machineName , ConnectionOptions options , string path  )
{
  ManagementScope scope = new ManagementScope ( );
  scope . Path = new ManagementPath ( @"\\" + machineName + path );
  scope . Options = options;
  scope . Connect ( );
  return scope;
}

// Method to retrieve the list of all COM ports.
public static List<PortInfo> FindComPorts ( )
{
  List<PortInfo> portList = new List<PortInfo> ( );
  ConnectionOptions options = PrepareOptions ( );
  ManagementScope scope = PrepareScope ( Environment . MachineName , options , @"\root\CIMV2" );

  // Prepare the query and searcher objects.
  ObjectQuery objectQuery = new ObjectQuery ( "SELECT * FROM Win32_PnPEntity WHERE ConfigManagerErrorCode = 0" );
  ManagementObjectSearcher portSearcher = new ManagementObjectSearcher ( scope , objectQuery );

  using ( portSearcher )
  {
    string caption = null;
    // Invoke the searcher and search through each management object for a COM port.
    foreach ( ManagementObject currentObject in portSearcher . Get ( ) )
    {
      if ( currentObject != null )
      {
        object currentObjectCaption = currentObject [ "Caption" ];
        if ( currentObjectCaption != null )
        {
          caption = currentObjectCaption . ToString ( );
          if ( caption . Contains ( "(COM" ) )
          {
            PortInfo portInfo = new PortInfo ( );
            portInfo . Name = caption . Substring ( caption . LastIndexOf ( "(COM" ) ) . Replace ( "(" , string . Empty ) . Replace ( ")" , string . Empty );
            portInfo . Description = caption;
            portList . Add ( portInfo );
          }
        }
      }
    }
  }
  return portList;
}