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WM_DEVICECHANGE

Top / WM_DEVICECHANGE

Notifies an application of a change to the hardware configuration of a device or the computer.

A window receives this message through its WindowProc function.

https://msdn.microsoft.com/ja-jp/library/windows/desktop/aa363480(v=vs.85).aspx

パラメータ

LRESULT CALLBACK WindowProc(HWND   hwnd,     // handle to window
                            UINT   uMsg,     // WM_DEVICECHANGE
                            WPARAM wParam,   // device-change event
                            LPARAM lParam ); // event-specific data

uMsg?

• WM_DEVICECHANGE

wParam

• DBT_DEVNODES_CHANGED	0x0007	A device has been added to or removed from the system.
  DBT_DEVICEARRIVAL	0x8000 (32768)	A device or piece of media has been inserted and is now available.
  DBT_DEVICEQUERYREMOVE?	0x8001	Permission is requested to remove a device or piece of media. Any application can deny this request and cancel the removal.
  DBT_DEVICEQUERYREMOVEFAILED?	0x8002	A request to remove a device or piece of media has been canceled.
  DBT_DEVICEREMOVEPENDING?	0x8003	A device or piece of media is about to be removed. Cannot be denied.
  DBT_DEVICEREMOVECOMPLETE?	0x8004	A device or piece of media has been removed.
  DBT_DEVICETYPESPECIFIC?	0x8005	A device-specific event has occurred.

Hardware Helper Library for C#

• http://www.codeproject.com/Articles/21503/Hardware-Helper-Library-for-C
• when the WM_DEVICECHANGE message arrives, we simply reload the entire list. There is no fancy method of determining which device was added or removed at this time,

Detecting Hardware Insertion and/or Removal

• http://www.codeproject.com/Articles/14500/Detecting-Hardware-Insertion-and-or-Removal
• A user-mode application to detect hardware add/remove with WM_DEVICECHANGE and RegisterDeviceNotification()
• by default, Windows OS will only post WM_DEVICECHANGE to
  • All applications with a top-level window, and
  • Only upon port and volume change.

メモ

• USBメモリを挿した時にはDBT_DEVICEARRIVAL/DBT_DEVICEREMOVECOMPLETE?が発生した。
• マウス/Webカメラの時にはDBT_DEVNODES_CHANGEDしか発生しなかった。
  • RegisterDeviceNotificationでGUID_DEVINTERFACE_USB_DEVICEを登録するとDBT_DEVICEARRIVAL/DBT_DEVICEREMOVECOMPLETE?がくるようになる。

関連

• RegisterDeviceNotification
• DEV_BROADCAST_HDR

参考

• http://www.codeproject.com/Articles/21503/Hardware-Helper-Library-for-C