Detecting USB drive insertion and removal using windows service and c#

You can also use WMI to detect insertion events. It's a little bit more complicated than monitoring for WM_CHANGEDEVICE messages, but it does not require a window handle which may be useful if you are running in the background as a service.

Try WM_CHANGEDEVICE handling.

My complete answer can be found here as a gist

I found the answer to determining the drive letter from the serial # from this question/answer How to get the drive letter of USB device using WMI

And I modified Phil Minor's code to make it reactive:

   public class UsbDetector : IUsbDetector
    {
        private const string Query = "SELECT * FROM {0} WITHIN 2 WHERE TargetInstance ISA 'Win32_USBHub'";
        private const string CreationEvent = "__InstanceCreationEvent";
        private const string DeletionEvent = "__InstanceDeletionEvent";
        private const int ReplayNumber = 1;

        private readonly Subject<USBDeviceInfo> adds = new Subject<USBDeviceInfo>();
        private readonly Subject<USBDeviceInfo> removes = new Subject<USBDeviceInfo>();

        public UsbDetector()
        {
            var bgwDriveDetector = new BackgroundWorker();
            bgwDriveDetector.DoWork += DoWork;
            bgwDriveDetector.RunWorkerAsync();
        }

        public IObservable<USBDeviceInfo> Adds => adds.AsObservable();

        public IObservable<USBDeviceInfo> Removes => removes.AsObservable();


        private void DoWork(object sender, DoWorkEventArgs e)
        {
            SubscribeToEvent(CreationEvent, adds);
            SubscribeToEvent(DeletionEvent, removes);
        }

        private static void SubscribeToEvent(string eventType, IObserver<USBDeviceInfo> observer)
        {
            WqlEventQuery wqlEventQuery = new WqlEventQuery(string.Format(Query, eventType));
            ManagementEventWatcher insertWatcher = new ManagementEventWatcher(wqlEventQuery);

            var observable = Observable.FromEventPattern<EventArrivedEventHandler, EventArrivedEventArgs>(
                h => insertWatcher.EventArrived += h,
                h => insertWatcher.EventArrived -= h).Replay(ReplayNumber);

            observable.Connect();
            observable.Select(a => a.EventArgs).Select(MapEventArgs).Subscribe(observer);
            insertWatcher.Start();
        }


        private static USBDeviceInfo MapEventArgs(EventArrivedEventArgs e)
        {
            ManagementBaseObject instance = (ManagementBaseObject)e.NewEvent["TargetInstance"];

            string deviceId = (string)instance.GetPropertyValue("DeviceID");
            string serialNr = deviceId.Substring(deviceId.LastIndexOf('\\')).Replace("\\", "");
            char driveLetter = GetDriveLetter(serialNr).First();

            return new USBDeviceInfo(deviceId, serialNr, driveLetter);
        }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Management;
using System.ComponentModel;

namespace ConsoleApplication4
{
  public  class usbState
    {
       public usbState()
        {

        }

   private void DeviceInsertedEvent(object sender, EventArrivedEventArgs e)
   {
       ManagementBaseObject instance = (ManagementBaseObject)e.NewEvent["TargetInstance"];
       foreach (var property in instance.Properties)
       {
           Console.WriteLine(property.Name + " = " + property.Value);
       }
   }

   private void DeviceRemovedEvent(object sender, EventArrivedEventArgs e)
   {
       ManagementBaseObject instance = (ManagementBaseObject)e.NewEvent["TargetInstance"];
       foreach (var property in instance.Properties)
       {
           Console.WriteLine(property.Name + " = " + property.Value);
       }
   } 

    public  void bgwDriveDetector_DoWork(object sender, DoWorkEventArgs e)
    {
        WqlEventQuery insertQuery = new WqlEventQuery("SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA 'Win32_USBHub'");

        ManagementEventWatcher insertWatcher = new ManagementEventWatcher(insertQuery);
        insertWatcher.EventArrived += new EventArrivedEventHandler(DeviceInsertedEvent);
        insertWatcher.Start();

        WqlEventQuery removeQuery = new WqlEventQuery("SELECT * FROM __InstanceDeletionEvent WITHIN 2 WHERE TargetInstance ISA 'Win32_USBHub'");
        ManagementEventWatcher removeWatcher = new ManagementEventWatcher(removeQuery);
        removeWatcher.EventArrived += new EventArrivedEventHandler(DeviceRemovedEvent);
        removeWatcher.Start();
    }

}



class Class1
{
       private static void Main(string[] args)
      {
          usbState  usb= new usbState();



          BackgroundWorker bgwDriveDetector = new BackgroundWorker();
          bgwDriveDetector.DoWork += usb.bgwDriveDetector_DoWork;
          bgwDriveDetector.RunWorkerAsync();
          bgwDriveDetector.WorkerReportsProgress = true;
          bgwDriveDetector.WorkerSupportsCancellation = true;

         // System.Threading.Thread.Sleep(100000);
           Console.ReadKey();

       }





}

}