WinEventProc callback function
An application-defined callback (or hook) function that the system calls in response to events generated by an accessible object. The hook function processes the event notifications as required. Clients install the hook function and request specific types of event notifications by calling SetWinEventHook.
The WINEVENTPROC type defines a pointer to this callback function. WinEventProc is a placeholder for the application-defined function name.
Syntax
void CALLBACK WinEventProc( HWINEVENTHOOK hWinEventHook, DWORD event, HWND hwnd, LONG idObject, LONG idChild, DWORD dwEventThread, DWORD dwmsEventTime );
Parameters
- hWinEventHook
-
Type: HWINEVENTHOOK
Handle to an event hook function. This value is returned by SetWinEventHook when the hook function is installed and is specific to each instance of the hook function.
- event
-
Type: DWORD
Specifies the event that occurred. This value is one of the event constants.
- hwnd
-
Type: HWND
Handle to the window that generates the event, or NULL if no window is associated with the event. For example, the mouse pointer is not associated with a window.
- idObject
-
Type: LONG
Identifies the object associated with the event. This is one of the object identifiers or a custom object ID.
- idChild
-
Type: LONG
Identifies whether the event was triggered by an object or a child element of the object. If this value is CHILDID_SELF, the event was triggered by the object; otherwise, this value is the child ID of the element that triggered the event.
- dwEventThread
-
Type: DWORD
Identifies the thread that generated the event, or the thread that owns the current window.
- dwmsEventTime
-
Type: DWORD
Specifies the time, in milliseconds, that the event was generated.
Return value
This callback function does not return a value.
Remarks
Within the hook function, the parameters hwnd, idObject, and idChild are used when calling AccessibleObjectFromEvent.
Servers generate events by calling NotifyWinEvent.
Create multiple callback functions to handle different events. For more information, see Registering a Hook Function.
Requirements
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Minimum supported client |
Windows 2000 Professional [desktop apps only] |
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Minimum supported server |
Windows Server 2003 [desktop apps only] |
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Redistributable |
Active Accessibility 1.3 RDK on Windows NT 4.0 with SP6 and later and Windows 95 |
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Header |
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See also