// usb消息定义 public const int WM_DEVICE_CHANGE = 0x219; public const int DBT_DEVICEARRIVAL = 0x8000; public const int DBT_DEVICE_REMOVE_COMPLETE = 0x8004; public const UInt32 DBT_DEVTYP_PORT = 0x00000003; [StructLayout(LayoutKind.Sequential)] struct DE