PeerFinder.CreateWatcher 方法

  • 參考

定義

命名空間:
Windows.Networking.Proximity
編輯

建立 PeerWatcher 物件的新實例，以動態探索對等應用程式。

public:
 static PeerWatcher ^ CreateWatcher();
 static PeerWatcher CreateWatcher();
public static PeerWatcher CreateWatcher();
function createWatcher()
Public Shared Function CreateWatcher () As PeerWatcher

傳回

PeerWatcher

PeerWatcher物件的實例，用於動態探索對等應用程式。

Windows 需求

應用程式功能
proximity

備註

您必須先呼叫 Start 方法，再呼叫 CreateWatcher 方法。

如果您多次呼叫 CreateWatcher 方法，您會收到相同 PeerWatcher 實例的參考。

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;
    }
}

適用於

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