PlayToSource.PlayNext Метод
Определение
Важно!
Некоторые сведения относятся к предварительной версии продукта, в которую до выпуска могут быть внесены существенные изменения. Майкрософт не предоставляет никаких гарантий, явных или подразумеваемых, относительно приведенных здесь сведений.
Подключает следующий исходный элемент Воспроизведения к целевому объекту Воспроизведения.
public:
virtual void PlayNext() = PlayNext;/// [Windows.Foundation.Metadata.Deprecated("PlayToSource may be altered or unavailable for releases after Windows 10. Instead, use CastingSource.", Windows.Foundation.Metadata.DeprecationType.Deprecate, 65536, Windows.Foundation.UniversalApiContract)]
void PlayNext();/// [Windows.Foundation.Metadata.Deprecated("PlayToSource may be altered or unavailable for releases after Windows 10. Instead, use CastingSource.", Windows.Foundation.Metadata.DeprecationType.Deprecate, 65536, "Windows.Foundation.UniversalApiContract")]
void PlayNext();[Windows.Foundation.Metadata.Deprecated("PlayToSource may be altered or unavailable for releases after Windows 10. Instead, use CastingSource.", Windows.Foundation.Metadata.DeprecationType.Deprecate, 65536, typeof(Windows.Foundation.UniversalApiContract))]
public void PlayNext();[Windows.Foundation.Metadata.Deprecated("PlayToSource may be altered or unavailable for releases after Windows 10. Instead, use CastingSource.", Windows.Foundation.Metadata.DeprecationType.Deprecate, 65536, "Windows.Foundation.UniversalApiContract")]
public void PlayNext();function playNext()Public Sub PlayNext ()- Атрибуты
Примеры
IReadOnlyList<Windows.Storage.StorageFile> imageList; // contains the list of images to show
bool streaming = false; // true when streaming using Play To; otherwise false
int timeLapse = 5; // time between images (5 seconds)
int imageSize = 600; // size of current displayed image
int thumbnailSize = 200; // size of "thumbnail" of next image
int currentImage = 0; // index of the current image from imageList
// Get the list of images from the Pictures folder and start the slide show.
async private void StartSlideShow()
{
var resultsLibrary = await
Windows.Storage.KnownFolders.PicturesLibrary.GetFilesAsync();
imageList = resultsLibrary;
if (imageList.Count > 0)
{
var image = QueueImage(0, true);
}
else
{
MessageBlock.Text = "There are no images in the Pictures library.";
}
}
// PlayNextImage
// Called when a new image is displayed due to a timeout.
// Removes the current image object and queues a new next image.
// Sets the next image index as the new current image, and increases the size
// of the new current image. Then sets the timeout to display the next image.
private async void PlayNextImage(int num)
{
// Stop the timer to avoid repeating.
if (timer != null) { timer.Stop(); }
await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
async () =>
{
SlideShowPanel.Children.Remove((UIElement)(SlideShowPanel.FindName("image" + num)));
var i = await QueueImage(num + 2, false);
currentImage = num + 1;
((Image)SlideShowPanel.FindName("image" + currentImage)).Width = imageSize;
});
timer = new Windows.UI.Xaml.DispatcherTimer();
timer.Interval = new TimeSpan(0, 0, timeLapse);
timer.Tick += delegate(object sender, object e)
{
PlayNextImage(num + 1);
};
timer.Start();
}
// QueueImage
// Called to create an image object for the displayed images.
private async System.Threading.Tasks.Task<Image> QueueImage(int num, bool isFirstImage)
{
// Create the image element for the specified image index and add to the
// slide show div.
Image image = new Image();
image.Width = isFirstImage ? imageSize : thumbnailSize;
image.Name = "image" + num;
image.VerticalAlignment = VerticalAlignment.Bottom;
var fileContents = await imageList[num % imageList.Count].OpenReadAsync();
var imageBitmap = new Windows.UI.Xaml.Media.Imaging.BitmapImage();
imageBitmap.SetSource(fileContents);
image.Source = imageBitmap;
await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
() =>
{
SlideShowPanel.Children.Add(image);
});
// If this is the first image of the slide show, queue the next image. Do
// not queue if streaming as images are already queued before
// streaming using Play To.
if (isFirstImage && !streaming)
{
var i = await QueueImage(num + 1, false);
timer = new Windows.UI.Xaml.DispatcherTimer();
timer.Interval = new TimeSpan(0, 0, timeLapse);
timer.Tick += delegate(object sender, object e)
{
PlayNextImage(num);
};
timer.Start();
}
// Use the transferred event of the Play To connection for the current image object
// to "move" to the next image in the slide show. The transferred event occurs
// when the PlayToSource.playNext() method is called, or when the Play To
// Receiver selects the next image.
image.PlayToSource.Connection.Transferred +=
async delegate(Windows.Media.PlayTo.PlayToConnection sender,
Windows.Media.PlayTo.PlayToConnectionTransferredEventArgs e)
{
currentImage = num + 1;
await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
() =>
{
((Image)SlideShowPanel.FindName("image" + currentImage)).Width = imageSize;
});
};
// Use the statechanged event to determine which action to take or to respond
// if the Play To Receiver is disconnected.
image.PlayToSource.Connection.StateChanged +=
async delegate(Windows.Media.PlayTo.PlayToConnection sender,
Windows.Media.PlayTo.PlayToConnectionStateChangedEventArgs e)
{
switch (e.CurrentState) {
case Windows.Media.PlayTo.PlayToConnectionState.Disconnected:
// If the state is disconnected and the current image index equals the
// num value passed to queueImage, then the image element is not connected
// to the Play To Receiver any more. Restart the slide show.
// Otherwise, the current image has been discarded and the slide show
// has moved to the next image. Clear the current image object and
// remove it from the slide show div.
if (currentImage == num)
{
await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
async () =>
{
MessageBlock.Text = "Slideshow disconnected";
// Cancel any existing timeout
if (timer != null) { timer.Stop(); }
// Clear all image objects from the slide show div
SlideShowPanel.Children.Clear();
// Reset the slide show objects and values to their beginning state
streaming = false;
DisconnectButton.Visibility = Visibility.Collapsed;
InstructionsBlock.Visibility = Visibility.Visible;
DisconnectButton.Click -= DisconnectButtonClick;
// Restart the slide show from the current image index
var i = await QueueImage(currentImage, true);
});
}
else
{
await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
() =>
{
image.PlayToSource.Next = null;
if (streaming)
{
SlideShowPanel.Children.Remove(image);
}
});
}
break;
case Windows.Media.PlayTo.PlayToConnectionState.Connected:
// If the state is connected and the previous state is disconnected,
// then the image element is newly connected. Queue up the next image so
// that it is loaded while the current image is being displayed.
// If the previous state is rendering, then the user has paused the slideshow
// on the Play To Receiver. Clear the current timeout until the user restarts
// the slide show.
await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
async () =>
{
if (e.PreviousState == Windows.Media.PlayTo.PlayToConnectionState.Disconnected)
{
var imageNext = await QueueImage(num + 1, false);
image.PlayToSource.Next = imageNext.PlayToSource;
}
else if (e.PreviousState == Windows.Media.PlayTo.PlayToConnectionState.Rendering)
{
if (timer != null) { timer.Stop(); }
}
if (currentImage == num)
{
MessageBlock.Text = "Slideshow connected";
}
});
break;
case Windows.Media.PlayTo.PlayToConnectionState.Rendering:
// If the state is rendering and the previous state is
// connected, then the Play To Receiver has restarted
// the slide show.
await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
() =>
{
if (e.PreviousState == Windows.Media.PlayTo.PlayToConnectionState.Connected)
{
// Clear any existing timeout.
if (timer != null) { timer.Stop(); }
// Restart the slide show.
timer = new Windows.UI.Xaml.DispatcherTimer();
timer.Interval = new TimeSpan(0, 0, timeLapse);
timer.Tick += delegate(object s, object args)
{
image.PlayToSource.PlayNext();
};
timer.Start();
}
if (currentImage == num)
{
MessageBlock.Text = "Slideshow rendering";
}
});
break;
}
};
return image;
}
Private imageList As IReadOnlyList(Of Windows.Storage.StorageFile) ' contains the list of images to show
Private streaming As Boolean = False ' true when streaming using Play To otherwise false
Private timeLapse As Integer = 5 ' time between images (5 seconds)
Private imageSize As Integer = 600 ' size of current displayed image
Private thumbnailSize As Integer = 200 ' size of "thumbnail" of next image
Private currentImage As Integer = 0 ' index of the current image from imageList
' Get the list of images from the Pictures folder and start the slide show.
Private Async Sub StartSlideShow()
Dim resultsLibrary =
Await Windows.Storage.KnownFolders.PicturesLibrary.GetFilesAsync()
imageList = resultsLibrary
If (imageList.Count > 0) Then
Dim image = QueueImage(0, True)
Else
MessageBlock.Text = "There are no images in the Pictures library."
End If
End Sub
' PlayNextImage
' Called when a new image is displayed due to a timeout.
' Removes the current image object and queues a new next image.
' Sets the next image index as the new current image, and increases the size
' of the new current image. Then sets the timeout to display the next image.
Private Async Sub PlayNextImage(num As Integer)
' Stop the timer to avoid repeating.
If timer IsNot Nothing Then timer.Stop()
Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
Async Sub()
SlideShowPanel.Children.Remove(CType(SlideShowPanel.FindName("image" & num), UIElement))
Dim i = Await QueueImage(num + 2, False)
currentImage = num + 1
CType(SlideShowPanel.FindName("image" & currentImage), Image).Width = imageSize
End Sub)
timer = New Windows.UI.Xaml.DispatcherTimer()
timer.Interval = New TimeSpan(0, 0, timeLapse)
AddHandler timer.Tick, Sub(sender As Object, e As Object)
PlayNextImage(num + 1)
End Sub
timer.Start()
End Sub
' QueueImage
' Called to create an image object for the displayed images.
Private Async Function QueueImage(num As Integer, isFirstImage As Boolean) As Task(Of Image)
' Create the image element for the specified image index and add to the
' slide show div.
Dim image = New Image()
image.Width = If(isFirstImage, imageSize, thumbnailSize)
image.Name = "image" & num
image.VerticalAlignment = VerticalAlignment.Bottom
Dim fileContents = Await imageList(num Mod imageList.Count).OpenReadAsync()
Dim imageBitmap = New BitmapImage()
imageBitmap.SetSource(fileContents)
image.Source = imageBitmap
Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
Sub()
SlideShowPanel.Children.Add(image)
End Sub)
' If this is the first image of the slide show, queue the next image. Do
' not queue if streaming as images are already queued before
' streaming using Play To.
If isFirstImage AndAlso Not streaming Then
Dim i = Await QueueImage(num + 1, False)
timer = New Windows.UI.Xaml.DispatcherTimer()
timer.Interval = New TimeSpan(0, 0, timeLapse)
AddHandler timer.Tick, Sub(sender As Object, e As Object)
PlayNextImage(num)
End Sub
timer.Start()
End If
' Use the transferred event of the Play To connection for the current image object
' to "move" to the next image in the slide show. The transferred event occurs
' when the PlayToSource.playNext() method is called, or when the Play To
' Receiver selects the next image.
AddHandler image.PlayToSource.Connection.Transferred,
Async Sub(sender As Windows.Media.PlayTo.PlayToConnection,
e As Windows.Media.PlayTo.PlayToConnectionTransferredEventArgs)
currentImage = num + 1
Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
Sub()
CType(SlideShowPanel.FindName("image" & currentImage), Image).Width = imageSize
End Sub)
End Sub
' Use the statechanged event to determine which action to take or to respond
' if the Play To Receiver is disconnected.
AddHandler image.PlayToSource.Connection.StateChanged,
Async Sub(sender As Windows.Media.PlayTo.PlayToConnection,
e As Windows.Media.PlayTo.PlayToConnectionStateChangedEventArgs)
Select Case e.CurrentState
Case Windows.Media.PlayTo.PlayToConnectionState.Disconnected
' If the state is disconnected and the current image index equals the
' num value passed to queueImage, then the image element is not connected
' to the Play To Receiver any more. Restart the slide show.
' Otherwise, the current image has been discarded and the slide show
' has moved to the next image. Clear the current image object and
' remove it from the slide show div.
If currentImage = num Then
Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
Async Sub()
MessageBlock.Text = "Slideshow disconnected"
' Cancel any existing timeout
If timer IsNot Nothing Then timer.Stop()
' Clear all image objects from the slide show div
SlideShowPanel.Children.Clear()
' Reset the slide show objects and values to their beginning state
streaming = False
DisconnectButton.Visibility = Visibility.Collapsed
InstructionsBlock.Visibility = Visibility.Visible
AddHandler DisconnectButton.Click, AddressOf DisconnectButtonClick
' Restart the slide show from the current image index
Dim i = Await QueueImage(currentImage, True)
End Sub)
Else
Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
Sub()
image.PlayToSource.Next = Nothing
If streaming Then
SlideShowPanel.Children.Remove(image)
End If
End Sub)
End If
Case Windows.Media.PlayTo.PlayToConnectionState.Connected
' If the state is connected and the previous state is disconnected,
' then the image element is newly connected. Queue up the next image so
' that it is loaded while the current image is being displayed.
' If the previous state is rendering, then the user has paused the slideshow
' on the Play To Receiver. Clear the current timeout until the user restarts
' the slide show.
Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
Async Sub()
If e.PreviousState = Windows.Media.PlayTo.PlayToConnectionState.Disconnected Then
Dim imageNext = Await QueueImage(num + 1, False)
image.PlayToSource.Next = imageNext.PlayToSource
ElseIf e.PreviousState = Windows.Media.PlayTo.PlayToConnectionState.Rendering Then
If timer IsNot Nothing Then timer.Stop()
End If
If currentImage = num Then
MessageBlock.Text = "Slideshow connected"
End If
End Sub)
Case Windows.Media.PlayTo.PlayToConnectionState.Rendering
' If the state is rendering and the previous state is
' connected, then the Play To Receiver has restarted
' the slide show.
Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
Sub()
If e.PreviousState = Windows.Media.PlayTo.PlayToConnectionState.Connected Then
' Clear any existing timeout.
If timer IsNot Nothing Then timer.Stop()
' Restart the slide show.
timer = New Windows.UI.Xaml.DispatcherTimer()
timer.Interval = New TimeSpan(0, 0, timeLapse)
AddHandler timer.Tick, Sub(s As Object, args As Object)
image.PlayToSource.PlayNext()
End Sub
timer.Start()
End If
If currentImage = num Then
MessageBlock.Text = "Slideshow rendering"
End If
End Sub)
End Select
End Function
Return image
End Function
Комментарии
Вы можете использовать метод PlayNext, чтобы остановить потоковую передачу текущего исходного носителя воспроизведения на целевой объект, а затем начать потоковую передачу источника Воспроизведения на, определяемого свойством Next в целевой объект Воспроизведения.
Пример использования свойства Next см. в разделе Приведение мультимедиа.