More info on http://www.techdays.be

2. A Message from the Team
We want to hear from you – app developers!
Microsoft will be hosting a live Q&A session via Lync for your company to
ask questions, or provide feedback, on the Windows 8 Proximity/NFC
APIs. You’ll have an opportunity to communicate directly with product
engineers who built the proximity APIs.
March 12th from 5 – 6 PM local Belgium time (GMT+1)
http://aka.ms/gwevca

3. Near Field Communication (NFC)
Enables devices to communicate wirelessly while in close proximity (3 to
4 cm) of each other
 "Devices" can be powered or passive (e.g., smart tag)
May be used to establish Bluetooth, WiFi, and WiFi Direct connections
for non-proximate transfers
Supported by many platforms, including Windows 8, Windows Phone
8, Android, and Symbian
Standards driven by NFC Forum (160+ members)

4. NFC Modes and Use Cases
NFC enables a multitude of "tap and do" scenarios which are intuitive to
users and require no setup
Read and write Tap devices to establish
information stored in peer-to-peer Tap a payment
passive NFC tags communication and share terminal to execute
("smart tags") content electronic payments
Reader/Writer Mode Peer-to-Peer Mode Card Emulation Mode

5. NFC Data Exchange Format (NDEF)
Lightweight, binary, platform-independent format for NFC messages with
variable-length payloads
Read and write
Or store them
them with
in inductively
smartphones
powered
and other
smart tags
mobile devices

6. NFC in WinRT
Tap For
NFC Socket
Connection Connection
ProximityDevice PeerFinder
Exchange NDEF messages and Exchange data using
Windows messages using SNEP Bluetooth, WiFi, or WiFi Direct*
* WiFi Direct supported in Windows 8 but not Windows Phone 8

7. Proximity Capability
Windows apps that use proximity networking must indicate that through
their manifests
Windows 8 Windows Phone 8

8. The ProximityDevice Class
Provides methods for driving NFC devices
 Publishing NDEF messages to devices and tags
 Subscribing to NDEF messages from devices and tags
 Identifying on-board proximity devices
Contains properties for retrieving transfer rates and other information
about proximity devices
Fires events when other proximity devices arrive and depart

9. Detecting NFC Support
var device = ProximityDevice.GetDefault();
if (device != null)
{
// This device supports NFC
}

10. Getting Device Information
var device = ProximityDevice.GetDefault();
if (device != null)
{
var id = device.DeviceId; // Device ID
var bps = device.BitsPerSecond; // Max transfer rate (bps)
var size = device.MaxMessageBytes; // Max message size (bytes)
}

11. Detecting Arrivals and Departures
var device = ProximityDevice.GetDefault();
if (device != null)
{
device.DeviceArrived += OnDeviceArrived;
device.DeviceDeparted += OnDeviceDeparted;
}
void OnDeviceArrived(ProximityDevice sender)
{
// Proximity device arrived
}
void OnDeviceDeparted(ProximityDevice sender)
{
// Proximity device departed
}

12. PublishMessage
ProximityDevice.PublishMessage publishes Windows.subtype messages
to other devices
 Supported by Windows and Windows Phone
 Not supported by other platforms
 subtype can be anything you want
 Supports transmission of string data
 Does not publish to smart tags
ProximityDevice.StopPublishingMessage stops publishing a message

13. Using PublishMessage
// Publish without a completed callback
device.PublishMessage("Windows.Sample", "Hello, NFC!");
// Publish with a completed callback
device.PublishMessage("Windows.Sample", "Hello, NFC!", OnMessageTransmitted);
.
.
.
void OnMessageTransmitted(ProximityDevice sender, long messageId)
{
// Stop publishing the message once it's delivered
device.StopPublishingMessage(messageId);
}

14. Subscribing to Messages
ProximityDevice.SubscribeForMessage subscribes to NDEF messages
of the specified type
 "Windows.subtype" messages
 "WindowsUri" messages for URIs
 "WriteableTag" messages for writeable tags
 "NDEF[:filter]" messages for other message types
 e.g., NDEF, NDEF:ext, and NDEF:wkt.U
ProximityDevice.StopSubscribingForMessage revokes a message
subscription

15. Using SubscribeForMessage
device.SubscribeForMessage("Windows.Sample", OnReceived);
.
.
.
void OnReceived(ProximityDevice sender, ProximityMessage message)
{
string type = message.MessageType; // e.g., "Windows.Sample"
string data = message.DataAsString; // e.g., "Hello, NFC!"
// Do this now, or do it later to continue subscribing
device.StopSubscribingForMessage(message.SubscriptionId);
}

17. The PeerFinder Class
Provides API for establishing socket connections via NFC for direct app-
to-app communications
 Methods for establishing connections
 Properties for feature detection, connecting to other platforms, and exerting control
over transport types
 Events signifying connection requests
TriggeredConnectionStateChanged event makes tap-to-connect gestures
simple and easy

18. Detecting Tap-to-Connect Support
if ((PeerFinder.SupportedDiscoveryTypes & PeerDiscoveryTypes.Triggered) != 0)
{
// This device supports tap-to-connect
}

19. Establishing a Socket Connection
if ((PeerFinder.SupportedDiscoveryTypes & PeerDiscoveryTypes.Triggered) != 0)
{
PeerFinder.TriggeredConnectionStateChanged += OnTriggered;
PeerFinder.Start();
}
void OnTriggered(object sender,
TriggeredConnectionStateChangedEventArgs e)
{
if (e.State == TriggeredConnectState.Completed)
{
var socket = e.Socket; // StreamSocket
PeerFinder.Stop();
}
}

20. Triggered Connection State
void OnTriggered(object sender, TriggeredConnectionStateChangedEventArgs e)
{
switch (e.State)
{
case TriggeredConnectState.Listening:
break;
case TriggeredConnectState.PeerFound: // OK to move devices apart
break;
case TriggeredConnectState.Connecting: // Establishing socket connection
break;
case TriggeredConnectState.Completed: // StreamSocket reference in e.Socket
break;
case TriggeredConnectState.Canceled: // Connection was closed
break;
case TriggeredConnectState.Failed: // Connection could not be established
break;
}
}

21. Controlling the Transport Type
// All values default to true
PeerFinder.AllowBluetooth = true; // Bluetooth
PeerFinder.AllowInfrastructure = true; // WiFi
PeerFinder.AllowWiFiDirect = true; // WiFi Direct (Win8 only)

22. Alternate (App) Identities
PeerFinder.AlternateIdentities enables apps on different platforms to
connect to each other
 e.g., Windows to Windows Phone
In a Windows app, add entry identifying corresponding app on Windows
Phone
 App ID = {App product ID}
In a Windows Phone app, add entry identifying corresponding app on
Windows
 App ID = {Package family name}!App

23. Enabling Windows Connections
PeerFinder.AlternateIdentities.Add(
"Windows", // Platform identifier
"f5bbba4f-c852-4e33-9e5d-54fe1c732524_ky5brtva589yy!App"
);

24. Enabling Windows Phone Connections
PeerFinder.AlternateIdentities.Add(
"WindowsPhone", // Platform identifier
"{b2c65896-3f48-4ea9-8c1c-773a17c38bff}"
);

26. PublishBinaryMessage
Publishes NDEF messages to devices and tags
 WriteTag messages for writing to smart tags
 Windows:WriteTag, WindowsUri:WriteTag, LaunchApp:WriteTag, and NDEF:WriteTag
 NDEF:WriteTag supports smart posters, Android Application Records (AARs), and more
 NDEF messages for publishing to other devices
 WindowsMime messages to other devices
Use NDEF Library for Proximity APIs for help formatting binary NDEF
messages

27. Getting an NFC Tag's Capacity
device.SubscribeForMessage("WriteableTag", OnReceived);
.
.
.
void OnReceived(ProximityDevice sender, ProximityMessage message)
{
var size = BitConverter.ToInt32(message.Data.ToArray(), 0);
}

28. Writing URIs to NFC Tags
using (var writer = new DataWriter { UnicodeEncoding = UnicodeEncoding.Utf16LE })
{
writer.WriteString("http://www.wintellect.com");
var buffer = writer.DetachBuffer();
device.PublishBinaryMessage("WindowsUri:WriteTag", buffer);
}

29. Writing Windows Launch Tags
using (var writer = new DataWriter { UnicodeEncoding = UnicodeEncoding.Utf16LE })
{
string tag =
"argument" + // Optional launch argument
"tWindowst" + // Platform identifier
"1ED5AEA5.AngryBirdsSpace_p2gbknwb5d8r2!App"; // App ID
writer.WriteString(tag);
var buffer = writer.DetachBuffer();
device.PublishBinaryMessage("LaunchApp:WriteTag", buffer);
}

30. Writing Windows Phone Launch Tags
using (var writer = new DataWriter { UnicodeEncoding = UnicodeEncoding.Utf16LE })
{
string tag =
"argument" + // Optional launch argument
"tWindowsPhonet" + // Platform identifier
"{afc3dfcf-8429-4e0d-9df8-4038939b5e75}"; // App ID
writer.WriteString(tag);
var buffer = writer.DetachBuffer();
device.PublishBinaryMessage("LaunchApp:WriteTag", buffer);
}

31. Writing Dual Launch Tags
using (var writer = new DataWriter { UnicodeEncoding = UnicodeEncoding.Utf16LE })
{
string tag =
"argument" +
"tWindowst" +
"1ED5AEA5.AngryBirdsSpace_p2gbknwb5d8r2!App" +
"tWindowsPhonet" +
"{afc3dfcf-8429-4e0d-9df8-4038939b5e75}";
writer.WriteString(tag);
var buffer = writer.DetachBuffer();
device.PublishBinaryMessage("LaunchApp:WriteTag", buffer);
}

32. Using Launch Arguments (Windows)
protected override void OnNavigatedTo(NavigationEventArgs e)
{
// If this page was activated from an NFC tag or a
// secondary tile, retrieve the launch argument
if (e.Parameter != null && e.Parameter != String.Empty)
{
string arg = (string)e.Parameter;
// TODO: Use the launch argument
}
}

33. Using Launch Arguments (Phone)
private const string _key = "ms_nfp_launchargs";
.
.
.
protected override void OnNavigatedTo(NavigationEventArgs e)
{
// If this page was activated from an NFC tag, retrieve the launch argument
if (NavigationContext.QueryString.ContainsKey(_key))
{
string arg = NavigationContext.QueryString[_key];
// TODO: Use the launch argument
}
}

35. NDEF Library for Proximity APIs
Free, open-source library for reading and writing NDEF
messages, including smart posters and AARs
Compatible with Windows 8 and WP8

36. Writing a Smart Poster Tag
var record = new NdefSpRecord();
record.Uri = "http://www.wintellect.com";
record.NfcAction = NdefSpActRecord.NfcActionType.DoAction;
record.AddTitle(new NdefTextRecord { Text = "Wintellect", LanguageCode = "en" });
var message = new NdefMessage { record };
device.PublishBinaryMessage("NDEF:WriteTag", message.ToByteArray().AsBuffer());

37. Reading a Smart Poster Tag
device.SubscribeForMessage("NDEF", OnMessageReceived);
...
void OnMessageReceived(ProximityDevice sender, ProximityMessage message)
{
var ndef = NdefMessage.FromByteArray(message.Data.ToArray());
foreach (NdefRecord record in ndef)
{
if (record.CheckSpecializedType(false) == typeof(NdefSpRecord))
{
var poster = new NdefSpRecord(record);
var uri = poster.Uri;
for (int i = 0; i < poster.TitleCount(); i++)
var title = poster.Titles[i].Text;
}
}
}

38. Writing an Android Launch Tag
var record = new NdefAndroidAppRecord();
record.PackageName = "com.adobe.reader";
var message = new NdefMessage { record };
device.PublishBinaryMessage("NDEF:WriteTag", message.ToByteArray().AsBuffer());

40. PublishUriMessage
Publishes URI messages to other devices
 Messages include standard NDEF URI records
 Compatible with Windows and non-Windows devices
 Only one URI message can be published at a time
URI messages launch URIs on target devices
 http:// protocol launches browser and shows the specified URL
(e.g., http://www.wintellect.com)
 Other protocols launch apps registered for those protocols and can include launch
parameters
Great way to launch apps on other platforms!

41. Launching a Browser
var uri = new Uri("http://www.wintellect.com");
device.PublishUriMessage(uri, OnMessageTransmitted);
.
.
.
void OnMessageTransmitted(ProximityDevice sender, long messageId)
{
// Message delivered
}

42. Launching Skype
var uri = new Uri("skype:lori.prosise?call");
device.PublishUriMessage(uri, OnMessageTransmitted);
.
.
.
void OnMessageTransmitted(ProximityDevice sender, long messageId)
{
// Message delivered
}

43. Subscribing to URI Messages
device.SubscribeForMessage("WindowsUri", OnUriReceived);
.
.
.
private async void OnUriReceived(ProximityDevice sender, ProximityMessage message)
{
var array = message.Data.ToArray();
var uri = Encoding.Unicode.GetString(array, 0, array.Length);
}