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Introduction and best practices for IsolatedStorageSettings

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[[Category:Draft]]
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[[Category:Code Examples]][[Category:Windows Phone]][[Category:Silverlight]][[Category:Files/Data]][[Category:Windows Phone 7.5]][[Category:Windows Phone 8]]
{{Abstract|This article shows most convenient way of using IsolatedStorageSettings.}}
+
{{Abstract|This article explains how to use  [http://msdn.microsoft.com/en-us/library/system.io.isolatedstorage.isolatedstoragesettings(v=vs.95).aspx IsolatedStorageSettings] and illustrates a helper class which enables using saving & retrieving (many) settings parameters easily.}}
{{ArticleMetaData <!--v1.2-->
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{{SeeAlso|
|sourcecode= [File:IsolatedStorageSample.zip]
+
[[Saving application preferences in Windows Phone]]
|sdk= [https://dev.windowsphone.com/en-us/downloadsdk]
+
}}
 +
{{ArticleMetaData <!-- v1.2 -->
 +
|sourcecode= [[File:IsolatedStorageSample.zip]]
 +
|installfile= <!-- Link to installation file (e.g. [[Media:The Installation File.sis]]) -->
 +
|devices= <!-- Devices tested against - e.g. ''devices=Nokia 6131 NFC, Nokia C7-00'') -->
 +
|sdk= [https://dev.windowsphone.com/en-us/downloadsdk WP SDK 8.0]
 
|platform= Windows Phone 7.5 and 8.0
 
|platform= Windows Phone 7.5 and 8.0
|keywords= IsolatedStorageSettings, Isolated Storage, User Settings-->
+
|devicecompatability= <!-- Compatible devices e.g.: All* (must have internal GPS) -->
|creationdate=20121109
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 +
|capabilities= <!-- Capabilities required by the article/code example (e.g. Location, NetworkServices. -->
 +
|keywords= IsolatedStorageSettings, Isolated Storage, User Settings
 +
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}}
  
 
== Introduction ==
 
== Introduction ==
[http://msdn.microsoft.com/en-us/library/system.io.isolatedstorage.isolatedstoragesettings(v=vs.95).aspx IsolatedStorageSettings] - is dictionary-like way for permanent storing values in  [http://msdn.microsoft.com/en-us/library/x7dzh4ws(v=vs.95).aspx Isolated Storage]. All you have to do to store a value is provide a key for this value and a value itself.
+
 
You can store there anything you want: user settings, layout information or application state. All settings from IsolatedStorageSettings are accessible after application rerun.
+
[http://msdn.microsoft.com/en-us/library/system.io.isolatedstorage.isolatedstoragesettings(v=vs.95).aspx IsolatedStorageSettings] is a dictionary for permanent storing values in  [http://msdn.microsoft.com/en-us/library/x7dzh4ws(v=vs.95).aspx Isolated Storage] in the form of ''key-value pair''. All that you have to do to store a value - is to provide a key for this value and a value itself.
In this tutorial we are going create a simple application that keeps one value and then we will extend it for more convenient use.
+
 
== Basic Sample ==
+
You can store anything you want that is serializable, for example: user settings, layout information or application state. All settings from {{Icode|IsolatedStorageSettings}} are accessible after application shutdown and run again.
 +
 
 +
In this tutorial we will create a simple application that keeps one boolean value and then we are going to extend it for more convenient use.
 +
 
 +
== Storing one setting with IsolatedStorageSettings ==
 
# Run Visual Studio 2012
 
# Run Visual Studio 2012
# Create new Windows Phone project (7.5 or 8.0)
+
# Create new Windows Phone project (7.1 or 8.0)
#Navigate to MainPage.xaml and replace all control content with one checkbox:
+
# Navigate to '''MainPage.xaml''' and replace all control content with one checkbox: <code xml>
<code xml><phone:PhoneApplicationPage x:Class="IsolatedStorageSample.MainPage"
+
<phone:PhoneApplicationPage x:Class="IsolatedStorageSample.MainPage"
 
                             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 
                             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 
                             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 
                             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Line 30: Line 51:
 
               Unchecked="chck_Unchecked"
 
               Unchecked="chck_Unchecked"
 
               VerticalAlignment="Top" />
 
               VerticalAlignment="Top" />
</phone:PhoneApplicationPage></code>
+
</phone:PhoneApplicationPage>
#Navigate to MainPage.xaml.cs and add some code here:
+
</code>
<code csharp>using System.IO.IsolatedStorage;
+
# Navigate to '''MainPage.xaml.cs''' and insert code for storing and retrieving the value: <code csharp>
 +
using System.IO.IsolatedStorage;
 
using System.Windows;
 
using System.Windows;
  
Line 85: Line 107:
 
     }
 
     }
 
}</code>
 
}</code>
#Run the application
+
# Run the application
<gallery>
+
#: As expected - the checkbox remembers last state before application shutdown.
File:IsolatedStorageIntro.SimpleApplication.png|Simple setting
+
#: [[File:IsolatedStorageIntro.SimpleApplication.png|200px|Simple setting]]
</gallery>
+
 
IsolatedStorageSettings is easy to use. But if you are going to have more then just one setting-value - syncing, keeping key name, checking if setting exists and saving each time it been updated may become a headache. Better way is to provide all this functionality by helper class only once.
+
Why do I use thread synchronization?  Because I do not know where else I will decide to call {{Icode|SaveSettings}} in the future, it could be {{Icode|ThreadPool}}, Timer callback or anything else.
== Improvement ==
+
{{Icode|IsolatedStorageSettings}} is easy to use.  
Easier way to work with IsolatedStorageSettings is to create a wrapper class around it. It would save the settings every time we update a value (in a thread safe way), it would automatically set default value if setting does not exist (and does not throw an exception when you try to access not existen value), and finally it keeps the key name - we have to provide it only once during property declaration.
+
 
Create two new classes:
+
But if you are going to have more than just one setting-value - syncing, keeping key name, checking if setting exists and saving each time it has been updated may become a headache. Better way is to implement all this functionality in a helper class only once.
<code csharp>using System.IO.IsolatedStorage;
+
 
 +
== Helper class for easy storage of more setting values==
 +
 
 +
Now we are going to create new class and implement logic for storing and retrieving setting values. With this, it should save the setting values every time we update it (in a thread safe manner), it should automatically set the default value if setting does not exist and finally it should keep the key name - we have to provide it only once at property declaration.
 +
 
 +
We create two new classes: {{Icode|IsolatedStoragePropertyHelper}} and {{Icode|IsolatedStorageProperty}} as illustrated below.
 +
 
 +
<code csharp>
 +
using System.IO.IsolatedStorage;
  
 
namespace IsolatedStorageSample
 
namespace IsolatedStorageSample
Line 175: Line 205:
 
         }
 
         }
 
     }
 
     }
}</code>
+
}
This class is not hard to understand and you can extend it as you want (may be you want to save values only on application shutdown?).
+
</code>
Using this class is easier as IsolatedStorageSettings:
+
 
<code csharp>namespace IsolatedStorageSample
+
You can extend this classes as you want (may be you want to save values only when application is shutting down?) or you can just copy this classes to your project and start working right now.
 +
Using {{Icode|IsolatedStorageProperty}} class is easier then {{Icode|IsolatedStorageSettings}}:
 +
 
 +
<code csharp>
 +
namespace IsolatedStorageSample
 
{
 
{
 
     using System.Windows;
 
     using System.Windows;
Line 184: Line 218:
 
     public partial class MainPage
 
     public partial class MainPage
 
     {
 
     {
 +
        //Setting declaration
 
         static readonly IsolatedStorageProperty<bool> SwitchProperty = new IsolatedStorageProperty<bool>("switch",true);
 
         static readonly IsolatedStorageProperty<bool> SwitchProperty = new IsolatedStorageProperty<bool>("switch",true);
 
          
 
          
Line 202: Line 237:
 
     }
 
     }
 
}</code>
 
}</code>
We are still working only around one setting but as you can see a lot of lines are gone!
+
We still have only one setting but a lot of lines are gone! - With ten or more property-settings this class become indispensable.
Lets create another setting - FirstRunTimeProperty:
+
 
<code csharp>using System;
+
Lets create another setting - {{Icode|FirstRunTimeProperty}}:
 +
 
 +
<code csharp>
 +
using System;
  
 
namespace IsolatedStorageSample
 
namespace IsolatedStorageSample
Line 244: Line 282:
 
         }
 
         }
 
     }
 
     }
}</code>
+
}
FirstRunTimeProperty lets me know when was first application run.
+
</code>
<gallery>
+
 
File:IsolatedStorageRunTime.png|First Run Time
+
{{Icode|FirstRunTimeProperty}} let us know when was first application run.
</gallery>
+
 
 +
[[File:IsolatedStorageRunTime.png|200px|First Run Time]]
 +
 
 
You can run the application two or more times to test it.
 
You can run the application two or more times to test it.
  
Good practice is to create a special static class, that would contain all your settings in it, so you can access any property in a program
+
A good practice is to create a special static class, that would contain all your settings in it, so you can access any property in a program at any time:
in any time you want, like this:
+
 
<code csharp>namespace IsolatedStorageSample
+
<code csharp>
 +
namespace IsolatedStorageSample
 
{
 
{
 
     public static class SettingsContainer
 
     public static class SettingsContainer
Line 263: Line 304:
 
         //...
 
         //...
 
     }
 
     }
}</code>
+
}
''The "platform categories" will be displayed here in '''preview''' only - Copy paste relevant categories into text here''
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</code>
 
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{{VersionHint|Versions will be visible from this template when viewed in preview. You can delete this or leave it in the page as it is not displayed in final version}}
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''Add categories below using category selector.''
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Revision as of 16:59, 9 January 2013

This article explains how to use IsolatedStorageSettings and illustrates a helper class which enables using saving & retrieving (many) settings parameters easily.

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Article Metadata
Code ExampleTested withCompatibility
Platform(s): Windows Phone 7.5 and 8.0
Windows Phone 8
Windows Phone 7.5
Article
Keywords: IsolatedStorageSettings, Isolated Storage, User Settings
Created: jinek (09 Nov 2012)
Last edited: jaaura (09 Jan 2013)

Introduction

IsolatedStorageSettings is a dictionary for permanent storing values in Isolated Storage in the form of key-value pair. All that you have to do to store a value - is to provide a key for this value and a value itself.

You can store anything you want that is serializable, for example: user settings, layout information or application state. All settings from IsolatedStorageSettings are accessible after application shutdown and run again.

In this tutorial we will create a simple application that keeps one boolean value and then we are going to extend it for more convenient use.

Storing one setting with IsolatedStorageSettings

  1. Run Visual Studio 2012
  2. Create new Windows Phone project (7.1 or 8.0)
  3. Navigate to MainPage.xaml and replace all control content with one checkbox:
    <phone:PhoneApplicationPage x:Class="IsolatedStorageSample.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}">
    <CheckBox Content="Switch option"
    Name="chck"
    Checked="chck_Checked"
    Unchecked="chck_Unchecked"
    VerticalAlignment="Top" />
    </phone:PhoneApplicationPage>
  4. Navigate to MainPage.xaml.cs and insert code for storing and retrieving the value:
    using System.IO.IsolatedStorage;
    using System.Windows;
     
    namespace IsolatedStorageSample
    {
    public partial class MainPage
    {
    /// <summary>
    /// Object for sync access to IsolatedStorage
    /// </summary>
    private readonly object _sync = new object();
     
    private const string SwitchKeyName = "switch";
     
    // Constructor
    public MainPage()
    {
    InitializeComponent();
    //checking if property exists, if no - create it
    if (!IsolatedStorageSettings.ApplicationSettings.Contains(SwitchKeyName))
    {
    IsolatedStorageSettings.ApplicationSettings[SwitchKeyName] = true;
    SaveSettings();
    }
     
    //the checkbox state initializing
    chck.IsChecked = (bool) IsolatedStorageSettings.ApplicationSettings[SwitchKeyName];
    }
     
    private void chck_Checked(object sender, RoutedEventArgs e)
    {
    IsolatedStorageSettings.ApplicationSettings[SwitchKeyName] = true;
    SaveSettings();
    }
     
    private void chck_Unchecked(object sender, RoutedEventArgs e)
    {
    IsolatedStorageSettings.ApplicationSettings[SwitchKeyName] = false;
    SaveSettings();
    }
     
    /// <summary>
    /// Saving settings to isolated storage
    /// </summary>
    private void SaveSettings()
    {
    lock (_sync)
    {
    IsolatedStorageSettings.ApplicationSettings.Save();
    }
    }
    }
    }
  5. Run the application
    As expected - the checkbox remembers last state before application shutdown.
    Simple setting

Why do I use thread synchronization? Because I do not know where else I will decide to call SaveSettings in the future, it could be ThreadPool, Timer callback or anything else. IsolatedStorageSettings is easy to use.

But if you are going to have more than just one setting-value - syncing, keeping key name, checking if setting exists and saving each time it has been updated may become a headache. Better way is to implement all this functionality in a helper class only once.

Helper class for easy storage of more setting values

Now we are going to create new class and implement logic for storing and retrieving setting values. With this, it should save the setting values every time we update it (in a thread safe manner), it should automatically set the default value if setting does not exist and finally it should keep the key name - we have to provide it only once at property declaration.

We create two new classes: IsolatedStoragePropertyHelper and IsolatedStorageProperty as illustrated below.

using System.IO.IsolatedStorage;
 
namespace IsolatedStorageSample
{
/// <summary>
/// Helper class is needed because IsolatedStorageProperty is generic and
/// can not provide singleton model for static content
/// </summary>
internal static class IsolatedStoragePropertyHelper
{
/// <summary>
/// We must use this object to lock saving settings
/// </summary>
public static readonly object ThreadLocker = new object();
 
public static readonly IsolatedStorageSettings Store = IsolatedStorageSettings.ApplicationSettings;
}
 
/// <summary>
/// This is wrapper class for storing one setting
/// Object of this type must be single
/// </summary>
/// <typeparam name="T">Any serializable type</typeparam>
public class IsolatedStorageProperty<T>
{
private readonly object _defaultValue;
private readonly string _name;
private readonly object _syncObject = new object();
 
public IsolatedStorageProperty(string name, T defaultValue = default(T))
{
_name = name;
_defaultValue = defaultValue;
}
 
/// <summary>
/// Determines if setting exists in the storage
/// </summary>
public bool Exists
{
get { return IsolatedStoragePropertyHelper.Store.Contains(_name); }
}
 
/// <summary>
/// Use this property to access the actual setting value
/// </summary>
public T Value
{
get
{
//If property does not exist - initializing it using default value
if (!Exists)
{
//Initializing only once
lock (_syncObject)
{
if (!Exists) SetDefault();
}
}
 
return (T) IsolatedStoragePropertyHelper.Store[_name];
}
set
{
IsolatedStoragePropertyHelper.Store[_name] = value;
Save();
}
}
 
private static void Save()
{
lock (IsolatedStoragePropertyHelper.ThreadLocker)
{
IsolatedStoragePropertyHelper.Store.Save();
}
}
 
public void SetDefault()
{
Value = (T) _defaultValue;
}
}
}

You can extend this classes as you want (may be you want to save values only when application is shutting down?) or you can just copy this classes to your project and start working right now. Using IsolatedStorageProperty class is easier then IsolatedStorageSettings:

namespace IsolatedStorageSample
{
using System.Windows;
 
public partial class MainPage
{
//Setting declaration
static readonly IsolatedStorageProperty<bool> SwitchProperty = new IsolatedStorageProperty<bool>("switch",true);
 
public MainPage()
{
InitializeComponent();
chck.IsChecked = SwitchProperty.Value;
}
private void chck_Checked(object sender, RoutedEventArgs e)
{
SwitchProperty.Value = true;
}
 
private void chck_Unchecked(object sender, RoutedEventArgs e)
{
SwitchProperty.Value = false;
}
}
}

We still have only one setting but a lot of lines are gone! - With ten or more property-settings this class become indispensable.

Lets create another setting - FirstRunTimeProperty:

using System;
 
namespace IsolatedStorageSample
{
using System.Windows;
 
public partial class MainPage
{
static readonly IsolatedStorageProperty<bool> SwitchProperty = new IsolatedStorageProperty<bool>("switch",true);
 
/// <summary>
/// Keeps first run time
/// </summary>
static readonly IsolatedStorageProperty<DateTime> FirstRunTimeProperty = new IsolatedStorageProperty<DateTime>("firstruntime", DateTime.Now);
 
public MainPage()
{
InitializeComponent();
chck.IsChecked = SwitchProperty.Value;
Loaded+=OnLoaded;
}
 
private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
{
//MessageBox.Show - could freeze main thread for a long time
//Dont let it freeze the constructor
MessageBox.Show(FirstRunTimeProperty.Value.ToString());
//This MessageBox always shows time of first run
}
 
private void chck_Checked(object sender, RoutedEventArgs e)
{
SwitchProperty.Value = true;
}
 
private void chck_Unchecked(object sender, RoutedEventArgs e)
{
SwitchProperty.Value = false;
}
}
}

FirstRunTimeProperty let us know when was first application run.

First Run Time

You can run the application two or more times to test it.

A good practice is to create a special static class, that would contain all your settings in it, so you can access any property in a program at any time:

namespace IsolatedStorageSample
{
public static class SettingsContainer
{
public static readonly IsolatedStorageProperty<bool> TestProperty1
= new IsolatedStorageProperty<bool>("TestProperty1");
public static readonly IsolatedStorageProperty<string> TestProperty2
= new IsolatedStorageProperty<string>("TestProperty2", "This is a test property");
//...
}
}
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