Usb.Events 11.1.1.1

Usb.Events

Subscribe to the Inserted and Removed events to be notified when a USB drive is plugged in or unplugged, or when a USB device is connected or disconnected. Usb.Events is a .NET Standard 2.0 library and uses WMI on Windows, libudev on Linux and IOKit on macOS.

How to use:

1. Include NuGet package from https://www.nuget.org/packages/Usb.Events

    <ItemGroup>
    <PackageReference Include="Usb.Events" Version="11.1.1.1" />
    </ItemGroup>
   

2. Subscribe to events:

    using Usb.Events;
   
    class Program
    {
    static void Main(string[] _)
    {
    using IUsbEventWatcher usbEventWatcher = new UsbEventWatcher();
   
    usbEventWatcher.UsbDeviceRemoved += (_, device) => Console.WriteLine("Removed:" + Environment.NewLine + device + Environment.NewLine);
   
    usbEventWatcher.UsbDeviceAdded += (_, device) => Console.WriteLine("Added:" + Environment.NewLine + device + Environment.NewLine);
   
    usbEventWatcher.UsbDriveEjected += (_, path) => Console.WriteLine("Ejected:" + Environment.NewLine + path + Environment.NewLine);
   
    usbEventWatcher.UsbDriveMounted += (_, path) =>
    {
    Console.WriteLine("Mounted:" + Environment.NewLine + path + Environment.NewLine);
   
    foreach (string entry in Directory.GetFileSystemEntries(path))
    Console.WriteLine(entry);
   
    Console.WriteLine();
    };
   
    Console.ReadLine();
    }
    }
   

Constructor parameters:

UsbEventWatcher(
 bool startImmediately = true, 
 bool addAlreadyPresentDevicesToList = false, 
 bool usePnPEntity = false, 
 bool includeTTY = false)

• Set startImmediately to false if you don't want to start immediately, then call Start().
• Set addAlreadyPresentDevicesToList to true to include already present devices in UsbDeviceList.
• Set usePnPEntity to true to query Win32_PnPEntity instead of Win32_USBControllerDevice in Windows.
• Set includeTTY to true to monitor the TTY subsystem in Linux (besides the USB subsystem).

Using Win32_PnPEntity vs Win32_USBControllerDevice

• Win32_PnPEntity
  • PRO: works for all devices
  • CON: is CPU intensive
  • CON: uses only 2 methods to find MountedDirectoryPath for storage devices (this should still work for most devices)
• Win32_USBControllerDevice
  • PRO: uses 3 methods to find MountedDirectoryPath for storage devices
  • PRO: in not CPU intensive
  • CON: for some devices it can stop reporting UsbDeviceAdded event after the device is added and removed a few times

Using Win32_USBControllerDevice is usually the better option.

Example:

Usb.Events.Example demonstrates how to use Windows SetupAPI.dll functions SetupDiGetClassDevs, SetupDiEnumDeviceInfo and SetupDiGetDeviceProperty together with DEVPKEY_Device_DeviceDesc, DEVPKEY_Device_BusReportedDeviceDesc and DEVPKEY_Device_FriendlyName to get "Device description", "Bus reported device description" and "Friendly name" of the Usb.Events.UsbDevice reported by the Usb.Events.IUsbEventWatcher.UsbDeviceAdded event.

How to build:

Usb.Events.csproj uses gcc to build UsbEventWatcher.Mac.dylib from UsbEventWatcher.Mac.c when run on macOS and to build UsbEventWatcher.Linux.so from UsbEventWatcher.Linux.c when run on Linux.

On Debian/Ubuntu based Linux distros you need to install:

gcc with:

sudo apt-get install build-essential

32-bit and 64-bit udev with:

sudo apt-get install libudev-dev:i386 libudev-dev:amd64

support for compiling 32-bit on 64-bit Linux:

sudo apt-get install gcc-multilib

Usb.Events.dll expects to find UsbEventWatcher.Linux.so and UsbEventWatcher.Mac.dylib in the working directory when it runs, so make sure to build the project on Linux and Mac before building the NuGet package on Windows.

32-bit Intel macOS:

gcc -shared -m32 ./Mac/UsbEventWatcher.Mac.c -o ./x86/Release/UsbEventWatcher.Mac.dylib -framework CoreFoundation -framework DiskArbitration -framework IOKit

32-bit Intel Linux:

gcc -shared -m32 ./Linux/UsbEventWatcher.Linux.c -o ./x86/Release/UsbEventWatcher.Linux.so -ludev -fPIC

64-bit Intel macOS:

gcc -shared -m64 ./Mac/UsbEventWatcher.Mac.c -o ./x64/Release/UsbEventWatcher.Mac.dylib -framework CoreFoundation -framework DiskArbitration -framework IOKit

64-bit Intel Linux:

gcc -shared -m64 ./Linux/UsbEventWatcher.Linux.c -o ./x64/Release/UsbEventWatcher.Linux.so -ludev -fPIC

32-bit ARM macOS:

gcc -shared -march=armv7-a+fp ./Mac/UsbEventWatcher.Mac.c -o ./arm/Release/UsbEventWatcher.Mac.dylib -framework CoreFoundation -framework DiskArbitration -framework IOKit

32-bit ARM Linux:

gcc -shared -march=armv7-a+fp ./Linux/UsbEventWatcher.Linux.c -o ./arm/Release/UsbEventWatcher.Linux.so -ludev -fPIC

64-bit ARM macOS:

gcc -shared -march=armv8-a ./Mac/UsbEventWatcher.Mac.c -o ./arm64/Release/UsbEventWatcher.Mac.dylib -framework CoreFoundation -framework DiskArbitration -framework IOKit

64-bit ARM Linux:

gcc -shared -march=armv8-a ./Linux/UsbEventWatcher.Linux.c -o ./arm64/Release/UsbEventWatcher.Linux.so -ludev -fPIC

To build 32-bit and 64-bit ARM versions of UsbEventWatcher.Linux.so on Windows, you need to install Docker.

Important macOS note:

Due to changes in macOS Gatekeeper that were introduced sometime between May 28, 2025 and July 15, 2025, simply building and running the code on macOS no longer works by default.
macOS may block the included .dylib files, reporting that it "couldn’t verify the software for malicious content".
To use the code successfully, the .dylib must be signed with a Developer ID Application certificate.

TO DO:

• Automatically mount USB drive on UsbDeviceAdded event in Linux
• Automatically mount USB drive on UsbDeviceAdded event in macOS

Version history:

• 11.1.1.1 (2025-11-30):
  • Fixed GetLinuxMountPoint in Linux - by @jkehne
  • Fixed memory leaks in macOS - by @hexxone
  • Fixed memory leaks in Linux
• 11.1.1.0 (2025-01-29):
  • Fixed GetChild in Linux - thanks to @M0ns1gn0r
• 11.1.0.1 (2024-01-05):
  • Added XML documentation
• 11.1.0.0 (2023-11-30):
  • Added UsbEvents.snk to sign the assembly with a strong name key
• 11.0.1.1 (2023-11-17):
  • Added 64-bit ARM support in macOS - thanks to @slater1
• 11.0.1.0 (2023-07-29):
  • Fixed InvalidOperationException in Linux and macOS - by @Frankh67
• 11.0.0.1 (2023-07-21):
  • Added 32-bit and 64-bit ARM support in Linux
• 11.0.0.0 (2023-07-16):
  • Added 32-bit support in Linux
• 10.1.1.1 (2023-06-04):
  • Fixed Dispose() to exit native monitor loop in macOS
• 10.1.1.0 (2023-06-01):
  • Fixed Dispose() to exit native monitor loop in Linux
  • Added bool usePnPEntity to use Win32_PnPEntity in Windows
• 10.1.0.1 (2023-04-21):
  • Added bool addAlreadyPresentDevicesToList in Windows
• 10.1.0.0 (2023-04-15):
  • Updated System.Management package reference from 4.7.0 to 7.0.0
• 10.0.1.1 (2021-11-09):
  • Added bool startImmediately = true to UsbEventWatcher constructor
  • Added void Start(bool includeTTY = false) to IUsbEventWatcher
• 10.0.1.0 (2021-11-01):
  • Added bool includeTTY = false to UsbEventWatcher constructor
  • Fixed a EnumerateDevices bug in Linux - thanks to @d79ima
• 10.0.0.1 (2021-10-31):
  • Fixed a false "device added" events bug in Linux - thanks to @d79ima
• 10.0.0.0 (2021-07-02):
  • Fixed a NullReferenceException in Linux and macOS - by @thomOrbelius
• 1.1.1.1 (2021-02-13):
  • Fixed a bug in Windows where MountedDirectoryPath wasn't set for a disk drive - thanks to @cksoft0807
• 1.1.1.0 (2021-02-01):
  • Fixed a memory leak in Linux function GetLinuxMountPoint - by @maskimthedog
  • Fixed a bug in Linux where after instantiating UsbEventWatcher, the list of devices was empty - by @maskimthedog
  • Added monitoring of TTY subsystem in Linux - by @maskimthedog
  • Fixed a bug in Linux where monitoring would stop upon error - by @maskimthedog
• 1.1.0.1 (2020-09-19):
  • Fixed a bug
• 1.1.0.0 (2020-08-01):
  • Added:
    • MountedDirectoryPath
    • IsMounted
    • IsEjected
  • Breaking changes:
    • DevicePath renamed to DeviceSystemPath
    • UsbDriveInserted renamed to UsbDriveMounted
    • UsbDriveRemoved renamed to UsbDriveEjected
    • UsbDeviceInserted renamed to UsbDeviceAdded
• 1.0.1.1 (2020-07-10):
  • Fixed a bug
• 1.0.1.0 (2020-07-04):
  • Events for all USB devices
• 1.0.0.1 (2020-07-07):
  • Fixed a bug
• 1.0.0.0 (2020-04-28):
  • Events for USB drives and USB storage devices

Supported platforms: