A spaghetti piece of code to list all raw input devices.

ListInputDevices.cs

using System;
using System.Runtime.InteropServices;

class Program
{
    [DllImport("user32.dll", CharSet = CharSet.Ansi, SetLastError = true)]
    private static extern uint GetRawInputDeviceList([In][Out] RawInputDeviceList[] RawInputDeviceList, ref uint NumDevices, uint Size);

    [DllImport("user32.dll", CharSet = CharSet.Ansi, SetLastError = true)]
    private static extern uint GetRawInputDeviceInfo(IntPtr hDevice, RawInputDeviceInfo command, IntPtr pData, ref uint size);

    public enum RawInputDeviceType : uint
    {
        MOUSE,
        KEYBOARD,
        HID
    }

    public enum RawInputDeviceInfo : uint
    {
        PREPARSEDDATA = 0x20000005U,
        DEVICENAME = 0x20000007U,
        DEVICEINFO = 0x2000000BU
    }

    public struct RawInputDeviceList
    {
        public IntPtr hDevice;
        public RawInputDeviceType Type;
    }

    static void Main(string[] args)
    {
        var devCnt = 0U;
        var dwSize = (uint)Marshal.SizeOf(typeof(RawInputDeviceList));

        GetRawInputDeviceList(null, ref devCnt, dwSize);

        if (devCnt == 0U)
        {
            Console.WriteLine("No input device found.");
            Console.ReadLine();
            return;
        }

        var devList = new RawInputDeviceList[devCnt];
        var listCnt = GetRawInputDeviceList(devList, ref devCnt, dwSize);

        for (var i = 0U; i < listCnt; i++)
        {
            var pcbSize = 0U;
            var devType = devList[(int)((UIntPtr)i)].Type;
            var hDevice = devList[(int)((UIntPtr)i)].hDevice;

            GetRawInputDeviceInfo(hDevice, RawInputDeviceInfo.DEVICENAME, IntPtr.Zero, ref pcbSize);

            if (pcbSize == 0) continue;

            var pData = Marshal.AllocHGlobal((int)pcbSize);
            GetRawInputDeviceInfo(hDevice, RawInputDeviceInfo.DEVICENAME, pData, ref pcbSize);

            var devName = Marshal.PtrToStringAnsi(pData);
            Console.WriteLine("{0} - {1}", devType, devName);

            Marshal.FreeHGlobal(pData);
        }

        Console.ReadLine();
    }
}