SHChangeNotifyRegister function (shlobj_core.h)
Registers a window to receive notifications from the file system or Shell, if the file system supports notifications.
ULONG SHChangeNotifyRegister( [in] HWND hwnd, int fSources, LONG fEvents, UINT wMsg, int cEntries, [in] const SHChangeNotifyEntry *pshcne );
A handle to the window that receives the change or notification messages.
One or more of the following values that indicate the type of events for which to receive notifications.
Interrupt level notifications from the file system.
Shell-level notifications from the shell.
Interrupt events on the whole subtree. This flag must be combined with the SHCNRF_InterruptLevel flag. When using this flag, notifications must also be made recursive by setting the fRecursive member of the corresponding SHChangeNotifyEntry structure referenced by pshcne to TRUE. Use of SHCNRF_RecursiveInterrupt on a single level view—for example, a PIDL that is relative and contains only one SHITEMID—will block event notification at the highest level and thereby prevent a recursive, child update. Thus, an icon dragged into the lowest level of a folder hierarchy may fail to appear in the view as expected.
Change notification events for which to receive notification. See the SHCNE flags listed in SHChangeNotify for possible values.
Message to be posted to the window procedure.
Number of entries in the pshcne array.
Type: const SHChangeNotifyEntry*
Returns a positive integer registration ID. Returns 0 if out of memory or in response to invalid parameters.
See the Change Notify Watcher Sample in the Windows Software Development Kit (SDK) for a full example that demonstrates the use of this function.
When a change notification event is raised, the message indicated by wMsg is delivered to the window specified by the hwnd parameter.
- If SHCNRF_NewDelivery is specified, the wParam and lParam values in the message should be passed to SHChangeNotification_Lock as the hChange and dwProcID parameters respectively.
- If SHCNRF_NewDelivery is not specified, wParam is a pointer to two PIDLIST_ABSOLUTE pointers, and lParam specifies the event. The two PIDLIST_ABSOLUTE pointers can be NULL, depending on the event being sent.
For performance reasons, multiple notifications can be combined into a single notification. For example, if a large number of SHCNE_UPDATEITEM notifications are generated for files in the same folder, they can be joined into a single SHCNE_UPDATEDIR notification.
The NTSHChangeNotifyRegister function, which is no longer available as of Windows Vista, was equivalent to SHChangeNotifyRegister with the SHCNRF_NewDelivery flag.
|Minimum supported client||Windows 2000 Professional [desktop apps only]|
|Minimum supported server||Windows 2000 Server [desktop apps only]|
|Header||shlobj_core.h (include Shlobj.h)|
|DLL||Shell32.dll (version 5.0 or later)|
|API set||ext-ms-win-shell-shell32-l1-2-1 (introduced in Windows 10, version 10.0.10240)|