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.

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