DBT_QUERYCHANGECONFIG event
The system broadcasts the DBT_QUERYCHANGECONFIG device event to request permission to change the current configuration (dock or undock). Any application can deny this request and cancel the change.
To broadcast this device event, the system uses the WM_DEVICECHANGE message with wParam set to DBT_QUERYCHANGECONFIG and lParam set to zero.
LRESULT CALLBACK WindowProc(
HWND hwnd, // handle to window
UINT uMsg, // WM_DEVICECHANGE
WPARAM wParam, // device-change event
LPARAM lParam // event-specific data
);
Parameters
-
hwnd
-
A handle to a window.
-
uMsg
-
The WM_DEVICECHANGE message identifier.
-
wParam
-
Set to DBT_QUERYCHANGECONFIG.
-
lParam
-
Set to zero.
Return value
Return TRUE to grant permission to change the configuration.
Return BROADCAST_QUERY_DENY to deny permission to change the configuration.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows XP |
| Minimum supported server |
Windows Server 2003 |
| Header |
|