ITVControl

[This is preliminary documentation and subject to change.]

The ITVControl interface is a sink that enables objects to receive notifications of changes in the state of WebTV for Windows.

When to Implement

Implement ITVControl if you are developing a television-aware control that resides in the WebTV for Windows container, or if your control needs notification of WebTV for Windows events.

Note  Currently, WebTV for Windows only sends notifications to applications running in the same process as WebTV for Windows. An example of such an application is a Microsoft® ActiveX® control or component called from an enhancement page that is currently being displayed by WebTV for Windows.

When to Use

WebTV for Windows calls the methods of ITVControl to notify registered objects of a change in the WebTV for Windows state.

Methods in Vtable Order

IUnknown Methods Description
QueryInterface Returns pointers to supported interfaces
AddRef Increments reference count
Release Decrements reference count

ITVControl Description
OnIdle Advises that idle-time processing is available.
Tune Advises that WebTV for Windows has tuned to a new channel.
TearDown Advises that WebTV for Windows is closing the current World Wide Web page.
SyncEvent Advises that a sync event has occurred.
EpisodeStatusChanged Advises that the status of an episode has changed.
PowerChange Advises that the system power is turning on or turning off.
OnTVFocus Advises that WebTV for Windows has gotten focus.
SetOutput Advises that the control should set an additional output device, for example a VCR.
GetCC Returns the closed-captioning status of the control.
SetCC Advises that the closed-captioning status has changed in WebTV for Windows.
EnableVideo Advises that the control that the status of the video display has changed.

Remarks

After your object has registered a sink, it should advise on the ITVControl connection point when it is user interface–activated, able to interact with the user, and revoke the connection point when it is user interface–deactivated, or hidden. In other words, the control should advise when it receives a IOleObject::DoVerb method call specifying the value OLEVERB_UIACTIVATE, OLEVERB_INPLACEACTIVATE, or OLEVERB_PRIMARY, and the control should revoke the connection point when it receives a IOleObject::DoVerb call specifying the value OLEVERB_HIDE.

To locate more information about the IOleObject interface and the DoVerb method, see Further Information on Television Services for the Client.

ITelevisionServices is derived from the IDispatch interface. To locate more information on IDispatch, a Component Object Model (COM) interface, see Further Information on Television Services for the Client.

QuickInfo

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

See Also

ITVViewer