IMediaEventEx::SetNotifyWindow method (control.h)

Article
07/27/2023

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The SetNotifyWindow method registers a window to process event notifications.

Syntax

HRESULT SetNotifyWindow(
  [in] OAHWND   hwnd,
  [in] long     lMsg,
  [in] LONG_PTR lInstanceData
);

Parameters

[in] hwnd

Handle to the window, or NULL to stop receiving event messages.

[in] lMsg

Window message to be passed as the notification.

[in] lInstanceData

Value to be passed as the lParam parameter for the lMsg message.

Return value

Returns S_OK if successful or E_INVALIDARG if the hwnd parameter is not a valid handle to a window.

Remarks

This method designates a window that will process event notifications. Whenever the Filter Graph Manager puts an event in the event queue, it will also post a message to the designated window. The hwnd parameter specifies the window, and the lMsg parameter specifies the message. The application should define a private window message for this purpose. The message's lParam parameter is set to the value of lInstanceData, and the wParam parameter is set to zero.

When the window receives the message, it should call the IMediaEvent::GetEvent method to retrieve the event. Events are asynchronous, so the queue might contain several events (or none). Call GetEvent repeatedly, until it returns an error code.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	control.h (include Dshow.h)
Library	Strmiids.lib