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This interface derives from IMediaEventand adds a method that allows registration of a window to receive messages when events occur.
When to Implement
This interface is implemented by the filter graph manager.
Unlike IMediaEvent, IMediaEventExis not available through Automation, and therefore cannot be called directly from Visual Basic.
The CMediaEvent Classsupports IMediaEventEx.
When to Use
This interface is used by applications to receive notification that an event has occurred. Applications can then avoid using a separate thread that waits until an event is set.
For a list of system-defined event notifications, see DirectShow Event Notification Codes.
Methods in Vtable Order
| IUnknown methods | Description |
|---|---|
| QueryInterface | Returns pointers to supported interfaces. |
| AddRef | Increments the reference count. |
| Release | Decrements the reference count. |
| IDispatch methods | Description |
| GetTypeInfoCount | Determines whether there is type information available for this dispinterface. |
| GetTypeInfo | Retrieves the type information for this dispinterface if GetTypeInfoCountreturned successfully. |
| GetIDsOfNames | Converts text names of properties and methods (including arguments) to their corresponding DISPIDs. |
| Invoke | Calls a method or accesses a property in this dispinterface if given a DISPID and any other necessary parameters. |
| IMediaEvent methods | Description |
| GetEventHandle | Retrieves a handle to a manual-reset event that will be signaled. |
| GetEvent | Retrieves the next notification event. |
| WaitForCompletion | Waits until the graph's operation has completed. |
| CancelDefaultHandling | Cancels any default handling of the specified event by the filter graph. |
| RestoreDefaultHandling | Restores default handling for this event. |
| FreeEventParams | Frees resources associated with the parameters to an event. |
| IMediaEventEx methods | Description |
| SetNotifyWindow | Registers a window that will handle messages when a specified event occurs. |
| SetNotifyFlags | Turns event notifications on or off. |
| GetNotifyFlags | Retrieves whether event notifications are on or off. |