当USB设备插入或者弹出时，Windows会产生一条全局消息：WM_DEVICECHANGE



我们需要做的是，获得这条消息的wParam参数，如果为DBT_DEVICEARRIVAL则表示有设备插入并可用，



如果是DBT_DEVICEREMOVECOMPLETE则表示有设备已经移除。再查看lParam参数为DBT_DEVTYP_VOLUME时，



就可以取出DEV_BROADCAST_VOLUME结构的卷号dbcv_unitmask，就知道是哪个卷被插入或者弹出。-When a USB device is inserted or pop-up, Windows will generate a global message: WM_DEVICECHANGE



We need to do is get this message wParam parameter, if it means that there is DBT_DEVICEARRIVAL device inserted and available,



If there is DBT_DEVICEREMOVECOMPLETE said equipment has been removed. Then view the lParam parameter is DBT_DEVTYP_VOLUME,



You can remove the volume number dbcv_unitmask DEV_BROADCAST_VOLUME structure, you know what the volume is inserted or ejected.