Handle device removal/addition

UsbService.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Windows.Forms;
+
+namespace WorkIndicator
+{
+    internal class UsbService : NativeWindow, IDisposable
+    {
+        public event Action DevicesChanged;
+
+        private const int WM_DEVICECHANGE = 0x0219;
+        private const int DBT_DEVICEARRIVAL = 0x8000;
+        private const int DBT_DEVICEREMOVECOMPLETE = 0x8004;
+        private const int DBT_DEVNODES_CHANGED = 0x0007;
+
+        private bool _isDisposed;
+
+        internal UsbService()
+        {
+            base.CreateHandle(new CreateParams());
+        }
+
+
+        protected override void WndProc(ref Message msg)
+        {
+            base.WndProc(ref msg);
+
+            if (msg.Msg == WM_DEVICECHANGE)
+            {
+                switch (msg.WParam.ToInt32())
+                {
+                    case DBT_DEVNODES_CHANGED:
+                    case DBT_DEVICEARRIVAL:
+                    case DBT_DEVICEREMOVECOMPLETE:
+                        DevicesChanged?.Invoke();
+                        break;
+                }
+            }
+        }
+
+        public void Dispose()
+        {
+            if (!_isDisposed)
+            {
+                base.DestroyHandle();
+
+                _isDisposed = true;
+
+                GC.SuppressFinalize(this);
+            }
+        }
+    }
+}