M4: Files and Storage in

Windows Phone 8

Target Agenda | Day 1

Module and Topic | 10-minute breaks after each session / 60-minute “meal break” Planned

Duration

1a - Introducing Windows Phone 8 Application Development | Part 1 50:00

1b - Introducing Windows Phone 8 Application Development | Part 2 50:00

2 - Designing Windows Phone Apps 50:00

3 - Building Windows Phone Apps 50:00

4 - Files and Storage on Windows Phone 8 50:00

Meal Break | 60-minutes 60:00

5 - Windows Phone 8 Application Lifecycle 50:00

6 - Background Agents 25:00

7 - Tiles and Lock Screen Notifications 25:00

8 - Push Notifications 30:00

9 - Using Phone Resources on Windows Phone 8 50:00

Target Agenda | Day 2

Module and Topic | 10-minute breaks after each session / 60-minute “meal break” Planned

Duration

10 - App to App Communication 35:00

11 - Network Communication on Windows Phone 8 50:00

12 - Proximity Sensors and Bluetooth 35:00

13 - Speech Input on Windows Phone 8 35:00

14 - Maps and Location on Windows Phone 8 35:00

15 - Wallet Support 25:00

16 - In App Purchasing 25:00

Meal Break | 60-minutes 60:00

17 - The Windows Phone Store 50:00

18 - Enterprise Applications in Windows Phone 8: Architecture and Publishing 50:00

19 - Windows 8 and Windows Phone 8 Cross Platform Development 50:00

20 – Mobile Web 50:00

• WP7.1IsolatedStorage and IsolatedStorageSettings APIs

• “Local Storage” and “Isolated Storage”

• Windows.Storage (Windows Phone Runtime) programming

• Special Folders

• Shared/Media

• Shared/ShellContent

• Shared/Transfers

• Exploring the local folder with ISET

Using Removable SD cards

Module Agenda

Not Covered in this Module…

• Local Database

• No change from WP 7.1

• See these Jump Start modules:

• http://channel9.msdn.com/Series/Mango-Jump-Start/Mango-Jump-Start-08a-

Application-Data-Storage-on-Windows-Phone--Part-1

• http://channel9.msdn.com/Series/Mango-Jump-Start/Mango-Jump-Start-08b-

Application-Data-Storage-on-Windows-Phone-Part-2

• SQLite database (native only)

Persistent Storage in

Windows Phone 8

Local Data Storage: Overview

• Package Manager installs

all app files into the

Installation Folder

• Read-only access from app

• Read-only reference

database

• Apps store data in

Local Folder

• Settings and properties in

the app dictionary

• Unstructured data in

Isolated Storage files

• Structured data in

database files

Application

Settings File

App

Application

Files

Package Manager

Installation

Folder WP7.1: “App Data”

WP8 Storage

APIs or

WP7 Isolated

Storage APIs

Install

DB

Database file

DB Database

File (r/o)

File Type/ API Installation

Folder Local Folder Example

Local Database data

context appdata:/ isostore:/

MyDataContext db = new MyDataContext ("isostore:/mydb.sdf")

Files access using

WP7.1 Isolated

Storage API

not supported

StorageFile and

StorageFolder

APIs

var isf = IsolatedStorageFile.GetUserStoreForApplication()

File access using

Windows.Storage

API via URIs

ms-appx:/// ms-

appdata:///local/

var file = await Windows.StorageFile.GetFileFromApplicationUriAsync( new Uri("ms-appdata:///local/AppConfigSettings.xml"));

File access using

Windows.Storage API

via StorageFolder

references

Windows. ApplicationModel. Package.Current. InstalledLocation

Windows.Storage. ApplicationData. Current. LocalFolder

var localFolder = Windows.Storage.ApplicationData.Current.LocalFolder; Windows.Storage.StorageFile storageFile = await localFolder.GetFileAsync("CaptainsLog.store");

Different Methods For Addressing Storage Locations

• Three ways of getting a reference to the same file:

// WP7.1 IsolatedStorage APIs

var isf = IsolatedStorageFile.GetUserStoreForApplication();

IsolatedStorageFileStream fs = new IsolatedStorageFileStream("CaptainsLog.store", FileMode.Open, isf));

...

// WP8 Storage APIs using URI

StorageFile storageFile = await Windows.Storage.StorageFile.GetFileFromApplicationUriAsync(

new Uri("ms-appdata:///local/CaptainsLog.store "));

...

// WP8 Storage APIs

Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;

Windows.Storage.StorageFile storageFile = await localFolder.GetFileAsync("CaptainsLog.store");

...

WP8 File Access Alternatives

Storing Data using WP7.1

Isolated Storage APIs

Isolated Storage Classes

• The IsolatedStorage classes are all in the System.IO.IsolatedStorage namespace

• IsolatedStorageFile

• Represents an isolated storage area containing files and directories

• IsolatedFileStream

• Exposes a file stream access to a file stored within isolated storage

• IsolatedStorageSettings

• Dictionary<(Of <(TKey, TValue>)>) that stores key-value pairs

in isolated storage

Saving Data

private void saveGameToIsolatedStorage(string message) { using (IsolatedStorageFile isf = IsolatedStorageFile.GetUserStoreForApplication()) { using (IsolatedStorageFileStream rawStream = isf.CreateFile("MyFile.store")) { StreamWriter writer = new StreamWriter(rawStream); writer.WriteLine(message); // save the message writer.Close(); } } }

Loading Data

private string loadString() { string result = null; using (IsolatedStorageFile isf = IsolatedStorageFile.GetUserStoreForApplication()) { if (isf.FileExists("Myfile.store") { using (IsolatedStorageFileStream rawStream = isf.OpenFile(filename, System.IO.FileMode.Open)) { StreamReader reader = new StreamReader(rawStream); result = reader.ReadLine(); reader.Close(); } } } return result; }

Demo 1: Using

Isolated Storage

Application Settings

• If you just want to store setting information

• Username = “Fred”

• TextColor = “Green”

• You can use the ApplicationSettings object in Isolated Storage

• You use this as you would a dictionary

• You then write the object to persistent storage

Saving Data in Settings

• The storage works as a dictionary

• But you have to remember to call Save when you have finished adding keys

void saveString(string message, string name) { IsolatedStorageSettings.ApplicationSettings[name] = message; IsolatedStorageSettings.ApplicationSettings.Save(); }

Loading from Settings

• Test for the key before you try to find it or you will get an exception thrown

string loadString(string name) { if (IsolatedStorageSettings.ApplicationSettings.Contains(name)) { return (string)IsolatedStorageSettings.ApplicationSettings[name]; } else { return null; } }

Demo 2: Using

Settings Storage

Using Windows Phone

Runtime Storage

Windows.Storage Classes

• Windows Phone Runtime storage classes are in the Windows.Storage namespace

• StorageFolder

• Represents a storage area containing files and directories

• StorageFile

• Represents a file and provides methods for manipulating them

• Not supported on Windows Phone 8:

• ApplicationData.LocalSettings

• Use custom file or IsolatedStorageSettings

Saving Data – Using StorageFolder

using System.IO; using Windows.Storage; … private async void saveToLocalFolderAsync(string message) { // Get a reference to the Local Folder StorageFolder localFolder = ApplicationData.Current.LocalFolder; // Create the file in the local folder, or if it already exists, just open it StorageFile storageFile = await localFolder.CreateFileAsync("Myfile.store", CreationCollisionOption.OpenIfExists); Stream writeStream = await storageFile.OpenStreamForWriteAsync(); using (StreamWriter writer = new StreamWriter(writeStream)) { await writer.WriteAsync(logData); } }

Loading Data

using System.IO; using Windows.Storage; … private async string loadStringAsync() { string theData = string.Empty; // Get a reference to the file in the Local Folder StorageFolder localFolder = ApplicationData.Current.LocalFolder; StorageFile storageFile = await localFolder.GetFileAsync(“Myfile.store")); // Open it and read the contents Stream readStream = await storageFile.OpenStreamForReadAsync(); using (StreamReader reader = new StreamReader(readStream)) { theData = await reader.ReadToEndAsync(); } return theData; }

Accessing Files Using ms-appdata:///local/ or ms-appx:///

// There's no FileExists method in WinRT, so have to try to open it and catch exception instead StorageFile storageFile = null; bool fileExists = false; try { // Try to open file using URI storageFile = await StorageFile.GetFileFromApplicationUriAsync( new Uri("ms-appdata:///local/Myfile.store")); fileExists = true; } catch (FileNotFoundException) { fileExists = false; } if (!fileExists) { await ApplicationData.Current.LocalFolder.CreateFileAsync("Myfile.store", CreationCollisionOption.FailIfExists); } ...

• Windows Phone 8 implementation of Windows.Storage is a subset of Windows 8 WinRT

• All data storage uses the LocalFolder (equivalent to WP7.1 IsolatedStorage)

• Not Supported:

• Roaming Data Store: ApplicationData.Current.RoamingFolder

• Temporary Data Store: ApplicationData.Current.TemporaryFolder

• Local Settings: ApplicationData.Current.LocalSettings

• Roaming Settings: ApplicationData.Current.RoamingSettings

Windows Phone 8 – Windows 8 Compatibility Only LocalFolder Supported

• In Windows 8, you can programmatically load an Image file that you have included in your

app package into a XAML <Image> element using the URI syntax, as follows:

RecipeImage.Source = new System.Windows.Media.Imaging.BitmapImage(

new Uri(@"ms-appx:///Images/french/French_1_600_C.jpg", UriKind.RelativeOrAbsolute));

• In Windows Phone 8, you cannot use the URI syntax in this way. Continue to use the

relative path to the image, as in Windows Phone OS 7.1:

RecipeImage.Source =

new System.Windows.Media.Imaging.BitmapImage("/Images/french/French_1_600_C.jpg");

Windows Phone 8 – Windows 8 Compatibility Programmatically Accessing Image Files

Demo 3: Using

Windows.Storage

Special Folders

Local Folder

• All read-write I/O operations restricted to

local folder

• Create a files and folder structure hierarchy

• Use Isolated Settings storage to store

application settings

Reserved Folders

• In addition to general data storage, the local folder is

used for the following special-use scenarios:

• Shared/Media - Apps can use this folder to display

album art in the Universal Volume Control (UVC)

while playing background audio

• Shared/ShellContent - Background images for Tiles

can be stored in isolated storage, but must be

located in this folder or a subfolder of it

• Shared/Transfers – Storage area used by the

Background File Transfer service

Data Serialization

and Deserialization

Data Serialization

• Data persistence and the app lifecycle

• App Launch

• Deserialize data from Isolated Storage

• App being dormant/tombstoned

• Serialize persistent data to Isolated Storage

• App being reactivated

• Deserialize data from Isolated Storage

• App being terminated

• Serialize persistent data to Isolated Storage

Not running

Launching

Running

Deactivated

/Closing

Why Serialize?

• Serializers write the properties of a collection of objects

into a file so they can be stored in persistent storage

• Deserializers reverse this: read data out of a file and use it

to ‘re-hydrate’ a collection of in-memory objects

• Many different serializers are available:

• XmlSerializer

• DataContractSerializer

• DataContractJsonSerializer

• Third party…

Serialization using DataContractSerializer

public class MyDataSerializer<TheDataType> { public static async Task SaveObjectsAsync(TheDataType sourceData, String targetFileName) { StorageFile file = await ApplicationData.Current.LocalFolder.CreateFileAsync( targetFileName, CreationCollisionOption.ReplaceExisting); var outStream = await file.OpenStreamForWriteAsync(); DataContractSerializer serializer = new DataContractSerializer(typeof(TheDataType)); serializer.WriteObject(outStream, sourceData); await outStream.FlushAsync(); outStream.Close(); } ... }

List<MyDataObjects> myObjects = ... await MyDataSerializer<List<MyDataObjects>>.SaveObjectsAsync(myObjects, "MySerializedObjects.xml");

• To use:

Deserialization using DataContractSerializer

public class MyDataSerializer<TheDataType> { public static async Task<TheDataType> RestoreObjectsAsync(string fileName) { StorageFile file = await ApplicationData.Current.LocalFolder.GetFileAsync(fileName); var inStream = await file.OpenStreamForReadAsync(); // Deserialize the objects. DataContractSerializer serializer = new DataContractSerializer(typeof(TheDataType)); TheDataType data = (TheDataType)serializer.ReadObject(inStream); inStream.Close(); return data; } ... }

List<MyDataObjects> myObjects = await MyDataSerializer<List<MyDataObjects>>.RestoreObjectsAsync("MySerializedObjects.xml");

• To use:

Demo 4: Serialization

to Local Folder

Tools: Isolated

Storage Explorer

Isolated Storage Explorer

• Isolated Storage Explorer is a command-line tool you use to list, copy, and replace files and

directories in Isolated Storage • Can be used on emulator or device

• Can be used for applications that target Windows Phone OS 7.0, 7.1 and 8.0

• Located at Program Files (x86)\Microsoft SDKs\Windows Phone\v8.0\Tools\IsolatedStorageExplorerTool

• Syntax:

• ISETool.exe <ts|rs|dir[:device-folder]> <xd|de> <Product GUID> [<desktop-path>]

• ts – Take snapshot

• rs – Restore snapshot

• dir – Lists the files or directories

• xd – target the emulator

• de – target device

• from the WPAppManifest.xml file for the app

• Desktop-path – directory on your computer where isolated storage files are written t o or copied from

Isolated Storage Explorer Example

Accessing SD Cards

External Storage (SD Card)

•Windows Phone 8 devices support SD cards

•App can discover what files are stored on a storage card • Must declare the ID_CAP_REMOVABLE_STORAGE capability in the application

manifest file

• Cannot write files - Access is Read Only

• Can only open file types for which your app has registered a file association in

WMAppManifest.xml

• You can only open files for which you have declared a File Association in WMAppManifest.xml

• Edit WMAppManifest.xml using the XML editor, not the Manifest editor

• Add a FileTypeAssociation element inside the Extensions element

• The Extensions element must follow immediately after the Tokens element

• Note that the ContentType attribute on the FileType element is required

<Extensions>

<FileTypeAssociation Name=“foo" TaskID="_default" NavUriFragment="fileToken=%s">

<SupportedFileTypes>

<FileType ContentType="application/foo">.foo</FileType>

</SupportedFileTypes>

</FileTypeAssociation>

</Extensions>

Declare a File Association to WMAppManifest.xml

API Description

ExternalStorageDevice Represents an SD card. Use the ExternalStorageDeviceExternalStorageID()

property to uniquely identify a card.

ExternalStorage.GetExternalStorage

DevicesAsync()

Returns a collection of SD cards that are inserted in the phone.

This collection will contain no more than one SD card.

ExternalStorageFolder Represents a folder on the SD card. Use the ExternalStorageFolderPath()

property to access the folder later.

ExternalStorageFile Represents a file on the SD card. Use the ExternalStorageFilePath()

property to access the file later.

ExternalStorageDeviceGetFile

Async() and

ExternalStorageDeviceGetFolder

Async()

Obtain a file or folder directly from the external storage device object.

External Storage APIs

Best Practices

Quota Management

• There are no quotas on Windows Phone!

• Applications must make careful use of space

• Use only is necessary

• Be transparent about storage usage

• Manage application data

• Delete temporary data and files when no longer required

• Consider synchronizing or archiving data to the cloud to reduce device storage

Serialization and Threads

• If your status information is a complex object you can easily save the object by

serializing it

• Serialization may slow down the saving and loading of data

• You should consider the use of threading in this situation

• Perform your loading and saving on a separate thread so that the application

stays responsive

The information herein is for informational

purposes only an represents the current view of

Microsoft Corporation as of the date of this

presentation. Because Microsoft must respond

to changing market conditions, it should not be

interpreted to be a commitment on the part of

Microsoft, and Microsoft cannot guarantee the

accuracy of any information provided after the

date of this presentation.

© 2012 Microsoft Corporation.

All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.

MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION

IN THIS PRESENTATION.