PeerFinder class

Applies to Windows and Windows Phone

Enables you to discover other instances of your app on nearby devices and create a socket connection between the peer apps by using a tap gesture or by browsing.

Syntax


var peerFinder = Windows.Networking.Proximity.PeerFinder;

Attributes

[MarshalingBehavior(Agile)]
[Threading(Both)]
[Version(0x06020000)]

Members

The PeerFinder class has these types of members:

Events

The PeerFinder class has these events.

EventDescription
ConnectionRequested Occurs when a remote peer requests a connection using the ConnectAsync method.
TriggeredConnectionStateChanged Occurs during a tap gesture from a remote peer.

 

Methods

The PeerFinder class has these methods. With C#, Visual Basic, and C++, it also inherits methods from the Object class.

MethodDescription
ConnectAsync Connects to a peer discovered by a call to the FindAllPeersAsync method.
CreateWatcher Creates a new instance of a PeerWatcher object for dynamic discovery of peer apps.
FindAllPeersAsync Asynchronously browses for peer devices that are running the same app within wireless range.
Start() Makes an app discoverable to remote peers.
Start(String) Makes an app discoverable to remote peers.
Stop Stops advertising for a peer connection.

 

Properties

The PeerFinder class has these properties.

PropertyAccess typeDescription

AllowBluetooth

Read/writeSpecifies whether the PeerFinder class may connect a StreamSocket object by using Bluetooth.

AllowInfrastructure

Read/writeSpecifies whether the PeerFinder class may connect to a StreamSocket object using TCP/IP.

AllowWiFiDirect

Read/writeSpecifies whether the PeerFinder class may connect a StreamSocket object by using Wi-Fi Direct.

AlternateIdentities

Read-onlyGets a list of alternate appId values to match with peer applications on other platforms.

DiscoveryData

Read/writeGets or sets user or device data to include during device discovery.

DisplayName

Read/writeGets or sets the name that identifies your computer to remote peers.

Role

Read/writeGets or sets the role of the app in peer-to-peer connections.

SupportedDiscoveryTypes

Read-onlyGets a value that indicates which discovery options are available to use with the PeerFinder class.

 

Remarks

Important  

The Proximity APIs do not provide authentication. You should avoid exchanging sensitive data with these APIs.

Examples


var started = false;

// Click event for "Advertise" button.
function advertiseForPeers(launchedFromTap) {
    Windows.Networking.Proximity.PeerFinder.displayName = displayNameTextBox.Text;

    if (Windows.Networking.Proximity.PeerFinder.supportedDiscoveryTypes &
        Windows.Networking.Proximity.PeerDiscoveryTypes.triggered) {

        Windows.Networking.Proximity.PeerFinder.addEventListener(
            "triggeredconnectionstatechanged", triggeredConnectionStateChanged);

        id("messageDiv").innerHTML +=
            "You can tap to connect a peer device that is " +
            "also advertising for a connection.<br />";
    } else {
        id("messageDiv").innerHTML +=
            "Tap to connect is not supported.<br />";
    }

    if (!launchedFromTap) {
        if (!(Windows.Networking.Proximity.PeerFinder.SupportedDiscoveryTypes &
              Windows.Networking.Proximity.PeerDiscoveryTypes.Browse)) {
            id("messageDiv").innerHTML +=
                "Peer discovery using Wi-Fi Direct is not supported.<br />";
        }
    }

    if (!started) {
        Windows.Networking.Proximity.PeerFinder.start();
        started = true;
    }
}

function triggeredConnectionStateChanged(e) {
    if (e.state === Windows.Networking.Proximity.TriggeredConnectState.peerFound) {
        id("messageDiv").innerHTML +=
            "Peer found. You may now pull your devices out of proximity.<br />";
    }
    if (e.state === Windows.Networking.Proximity.TriggeredConnectState.completed) {
        id("messageDiv").innerHTML += "Connected. You may now send a message.<br />";
        sendMessage(e.socket);
    }
}


// Click event for "Browse" button.
function findPeers() {
    if (Windows.Networking.Proximity.PeerFinder.supportedDiscoveryTypes &
        Windows.Networking.Proximity.PeerDiscoveryTypes.browse) {

        Windows.Networking.Proximity.PeerFinder.findAllPeersAsync().done(
    function (peerInfoCollection) {
        if (peerInfoCollection.length > 0) {
            // Connect to first peer found - example only.
            // In your app, provide the user with a list of available peers.
            connectToPeer(peerInfoCollection[0]);
        }
    },
    function (err) {
        id("messageDiv").innerHTML += "Error finding peers: " + err + "<br />";
    });
    } else {
        id("messageDiv").innerHTML +=
        "Peer discovery using Wi-Fi Direct is not supported.<br />";
    }
}

function connectToPeer(peerInfo) {
    id("messageDiv").innerHTML += ("Peer found. Connecting to " + peerInfo.displayName + "<br />");
    Windows.Networking.Proximity.PeerFinder.connectAsync(peerInfo).done(
        function (socket) {
            id("messageDiv").innerHTML += "Connection successful. You may now send messages.<br />";
            sendMessage(socket);
        },
        function (err) {
            id("messageDiv").innerHTML += "Connection failed: " + err + "<br />";
        });

    requestingPeer = null;
}

function stopFindingPeers() {
    Windows.Networking.Proximity.PeerFinder.stop();
    started = false;
    if (proximitySocket != null) { closeSocket(); }
}

// Handle external connection requests.
var requestingPeer;

function connectionRequested(e) {
    id("messageDiv").innerHTML +=
        "Connection requested by " + e.peerInformation.DisplayName + ". " +
        "Click 'Accept Connection' to connect.";
    requestingPeer = e.PeerInformation;
}

function acceptConnection() {
    if (requestingPeer == null) {
        id("messageDiv").innerHTML += "No peer connection has been requested.";
        return;
    }

    connectToPeer(requestingPeer);
}


Requirements

Minimum supported client

Windows 8 [Windows Store apps only]

Minimum supported server

Windows Server 2012 [Windows Store apps only]

Minimum supported phone

Windows Phone 8

Namespace

Windows.Networking.Proximity
Windows::Networking::Proximity [C++]

Metadata

Windows.winmd

Capabilities

proximity
ID_CAP_PROXIMITY [Windows Phone]
ID_CAP_NETWORKING [Windows Phone]

See also

Proximity and Tapping (JavaScript)
Proximity and Tapping (C#/VB/C++)
Samples
Proximity sample

 

 

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