PeerFinder.CreateWatcher 方法
定义
重要
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创建 PeerWatcher 对象的新实例，用于动态发现对等应用。
public:
static PeerWatcher ^ CreateWatcher(); static PeerWatcher CreateWatcher();public static PeerWatcher CreateWatcher();function createWatcher()Public Shared Function CreateWatcher () As PeerWatcher返回
用于动态发现对等应用的 PeerWatcher 对象的实例。
Windows 要求
| 应用功能 |
proximity
|
注解
在调用 CreateWatcher 方法之前，必须先调用 Start 方法。
如果多次调用 CreateWatcher 方法，将收到对同一 PeerWatcher 实例的引用。
private PeerWatcher _peerWatcher;
private bool _peerWatcherIsRunning = false;
private bool _peerFinderStarted = false;
// The list of peers discovered by the PeerWatcher.
ObservableCollection<PeerInformation> _discoveredPeers = new ObservableCollection<PeerInformation>();
void PeerFinder_StartPeerWatcher(object sender, RoutedEventArgs e)
{
if (!_peerFinderStarted)
{
// PeerFinder must be started first.
return;
}
if (_peerWatcherIsRunning)
{
// PeerWatcher is already running.
return;
}
try
{
if (_peerWatcher == null)
{
_peerWatcher = PeerFinder.CreateWatcher();
// Add PeerWatcher event handlers. Only add handlers once.
_peerWatcher.Added += PeerWatcher_Added;
_peerWatcher.Removed += PeerWatcher_Removed;
_peerWatcher.Updated += PeerWatcher_Updated;
_peerWatcher.EnumerationCompleted += PeerWatcher_EnumerationCompleted;
_peerWatcher.Stopped += PeerWatcher_Stopped;
}
// Empty the list of discovered peers.
_discoveredPeers.Clear();
// Start the PeerWatcher.
_peerWatcher.Start();
_peerWatcherIsRunning = true;
}
catch (Exception ex)
{
// Exceptions can occur if PeerWatcher.Start is called multiple times or
// PeerWatcher.Start is called the PeerWatcher is stopping.
}
}
protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
{
if (_peerWatcher != null)
{
// Remove event handlers.
_peerWatcher.Added -= PeerWatcher_Added;
_peerWatcher.Removed -= PeerWatcher_Removed;
_peerWatcher.Updated -= PeerWatcher_Updated;
_peerWatcher.EnumerationCompleted -= PeerWatcher_EnumerationCompleted;
_peerWatcher.Stopped -= PeerWatcher_Stopped;
_peerWatcher = null;
}
}