ITVControl::EnableVideo

[This is preliminary documentation and subject to change.]

The EnableVideo method advises that the status of the video display has changed.

HRESULT EnableVideo(
  VARIANT_BOOL bEnable,        
  int iReason  
);
 

Parameters

bEnable

A boolean value that indicates whether the control should display video. If bEnable is VARIANT_TRUE, video should be enabled. If bEnable is VARIANT_FALSE, video should be disabled.

iReason

If bEnable is VARIANT_FALSE, this parameter contains a value indicating the reason that video is disabled. If bEnable is VARIANT_TRUE, this parameter is not used. The supported values are listed in the following table:

Value	Description
kePrimaryMonitor	Video is not supported off of the primary monitor. This can occur in a multiple-monitor environment when the user drags the WebTV for Windows window from the primary monitor to a secondary montor. Because video is not supported on secondary monitors, it is disabled.

Return Values

WebTV for Windows ignores the value returned by this method.

Remarks

WebTV for Windows calls EnableVideo on all registered ITVControl sinks when the status of video display changes. For example, in a multiple-monitor environment if the user drags the WebTV for Windows window off of the primary monitor, video is no longer available because video is not supported on secondary monitors. In that case, WebTV for Windows calls EnableVideo(FALSE, kePrimaryMonitor) on all registered controls to inform them that video is disabled. The iReason parameter contains extended information explaining the reason that video was disabled. The control can then handle the event, presenting a message box to the user explaining why video was lost. When the WebTV for Windows window is moved back onto the primary monitor and video support is regained, WebTV for Windows calls EnableVideo( VARIANT_TRUE, 0 ) on all registered controls to advise them that video is re-enabled.

If a control registers an ITVControl sink while video is disabled, WebTV for Windows immediately sends an EnableVideo(FALSE, iReason) notification to the control. If the control does not receive this notification, it should assume that video is enabled. WebTV for Windows does not send a EnableVideo(TRUE, 0) message to newly registered controls. WebTV for Windows only calls EnableVideo(TRUE, 0) when video is re-enabled following a previous call to EnableVideo(FALSE, iReason).

QuickInfo

  Windows NT: Unsupported.
  Windows: Requires Windows 98.
  Windows CE: Unsupported.
  Header: Declared in tvdisp.odl.
  Import Library: User-defined.
  Unicode: Yes.