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VideoTrackList

Namespace: SpawnDev.SpawnJS.JSObjects
Inherits: EventTarget, IEnumerable<VideoTrack>
Source: JSObjects/VideoTrackList.cs
MDN Reference: VideoTrackList on MDN

The VideoTrackList interface is used to represent a list of the video tracks contained within a <video> element, with each track represented by a separate VideoTrack object in the list. Retrieve an instance of this object with HTMLMediaElement.videoTracks. The individual tracks can be accessed using array syntax or functions such as forEach() for example. https://developer.mozilla.org/en-US/docs/Web/API/VideoTrackList

Properties

Property Type Access Description
Length int get Returns the number of track objects in the list.
SelectedIndex int get The index of the currently selected track, if any, or −1 otherwise.

Methods

Method Return Type Description
GetEnumerator() IEnumerator<VideoTrack>
GetTrackById(string id) VideoTrack? Returns the track found within the list whose id matches the specified string. If no match is found, null is returned.

Events

Event Type Description
OnAddTrack ActionEvent<TrackEvent> Fired when a new track has been added to the media element.
OnChange ActionEvent<Event> Fired when a track has been enabled or disabled.
OnRemoveTrack ActionEvent<TrackEvent> Fired when a track has been removed from the media element.

Examples

SpawnDev.SpawnJS Mapping Note: The JavaScript examples below show the standard Web API usage. In SpawnDev.SpawnJS, the same API is available with C# conventions:

  • Properties and methods use PascalCase (e.g., readyState becomes ReadyState)
  • Events use ActionEvent with +=/-= (e.g., addEventListener("click", fn) becomes OnClick += handler)
  • Async methods return Task<T> instead of Promise<T>
  • Objects should be disposed with using statements
  • Access via JS.Get<VideoTrackList>(...) or constructor new VideoTrackList(...)

Getting a media element's video track list

const videoTracks = document.querySelector("video").videoTracks;

Monitoring track count changes

videoTracks.onaddtrack = updateTrackCount;
videoTracks.onremovetrack = updateTrackCount;

function updateTrackCount(event) {
  trackCount = videoTracks.length;
  drawTrackCountIndicator(trackCount);
}

See full example on MDN