MICROSOFT_PRESS_EBOOK_PROGRAMMING_WINDOWS_8_APPS_WITH_HTML_CSS_AND_JAVASCRIPT_PDF

o
Set PlayToSource.next property to the msPlayToSource of another element for continual
playing.
• Pick up the media element’s ended event to stage additional media
Another approach, as demonstrated in the Media Play To sample, is to go ahead and play media
locally and then let the user choose a PlayTo device on the fly from the Devices charm. In this case you
don’t need to do anything because Windows will pick up the current playback element and direct it
accordingly. But the app can listen to the statechanged event of the element’s msPlayToSource.-
connection object (a PlayToConnection) that will fire when the user selects a PlayTo device and when
other changes happen.
Generally speaking, PlayTo is primarily intended for streaming to a media receiver device that’s
probably connected to a TV or other large screen. This way you can select local content on a Windows 8
device and send it straight to that receiver. But it’s also possible to make a software receiver—that is, an
app that can receive streamed content from a PlayTo source. The PlayToReceiver sample does exactly
this, and when you run it on another device on your local network, it will show up in the Devices charms
as follows:
You can even run the app from your primarily machine using the remote debugging tools of Visual
Studio, allowing you to step through the code of both source and receiver apps at the same time!
(Another option is to run Windows Media Player on one machine and check its Stream > Allow Remote
Control of My Player menu option. This should make that machine appear in the PlayTo target list.)
To be a receiver, an app will generally want to declare some additional networking capabilities in the
manifest—namely, Internet (Client & Server) and Private Networks (Client & Server)—otherwise it won’t
see much action! It then creates an instance of Windows.Media.PlayTo.PlayToReceiver, as shown in the
PlayTo Receiver sample’s startPlayToReceiver function (js/audiovideoptr.js):
function startPlayToReceiver() {
if (!g_receiver) {
g_receiver = new Windows.Media.PlayTo.PlayToReceiver();
}
464