IsolatedStorageSettings Class (System.IO.IsolatedStorage)

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.NET Framework Class Library for Silverlight

IsolatedStorageSettings Class

Provides a Dictionary<(Of <(TKey, TValue>)>) that stores key-value pairs in isolated storage.

Namespace: System.IO.IsolatedStorage
Assembly: System.Windows (in System.Windows.dll)

Syntax

Visual Basic (Declaration)

Public NotInheritable Class IsolatedStorageSettings _
    Implements IDictionary(Of String, Object),  _
    ICollection(Of KeyValuePair(Of String, Object)), IEnumerable(Of KeyValuePair(Of String, Object)),  _
    IDictionary, ICollection, IEnumerable

Visual Basic (Usage)

Dim instance As IsolatedStorageSettings

public sealed class IsolatedStorageSettings : IDictionary<string, Object>, 
    ICollection<KeyValuePair<string, Object>>, IEnumerable<KeyValuePair<string, Object>>, 
    IDictionary, ICollection, IEnumerable

Exceptions

Exception	Condition
ArgumentNullException	key is nullNothingnullptra null reference (Nothing in Visual Basic). This exception is thrown when you attempt to reference an instance of the class by using an indexer and the variable you pass in for the key value is nullNothingnullptra null reference (Nothing in Visual Basic).

Remarks

IsolatedStorageSettings provide a convenient way to store user specific data as key-value pairs in a local IsolatedStorageFile. A typical use is to save settings, such as the number of images to display per page, page layout options, and so on.

User settings can be specific to an application or shared across applications in the same domain. ApplicationSettings are stored as per-application, per-computer, and per-user settings. Their scope is determined by the full path of the application .xap file. SiteSettings are stored as per-domain, per-computer, and per-user settings. Their scope is determined by the sub-domain that hosts the application .xap file. For example, an application at http://www.contoso.com/site1/application.xap will have different ApplicationSettings than an application at http://www.contoso.com/site2/application.xap. However, both applications will share the same SiteSettings because they are hosted on the same sub-domain.

Note:
The .xap files are not accessed directly; they are hosted within a Web page.

Like all data stored in isolated storage using Silverlight 2, IsolatedStorageSettings are stored locally on the user's computer. In Windows Vista, the information is stored in the AppData\LocalLow directory. For other operating system versions, including those on the Apple Macintosh, information is stored in the AppData\Local directory. Values stored in isolated storage are stored locally and are not available for roaming.

Examples

The following code example creates an isolated storage settings dictionary, gets a name from the user, stores the name, and then retrieves the name. The name is used in a greeting that is displayed when the page is launched. The code example also enables the user to change, view, and delete the stored name.

<UserControl x:Class="IsolatedStorageSample.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    FontFamily="Trebuchet MS" FontSize="11"
    Width="500" Height="300">
    <Grid x:Name="LayoutRoot" Background="White">
        <StackPanel VerticalAlignment="Top" >
            <TextBlock x:Name="tbGreeting" FontSize="24" />    
            <StackPanel Height="30" Orientation="Horizontal" Margin="10">
                <TextBlock Text="Name:      " VerticalAlignment="Center"/>
                <TextBox x:Name="tbName" Width="230" Margin="0,0,5,0"/>
                <Button x:Name="btnAddName" Content="Add" Click="btnAddName_Click" />
                <Button x:Name="btnChangeName" Content="Change" Click="btnChangeName_Click" />
                <Button x:Name="btnRemoveName" Content="Remove" Click="btnRemoveName_Click" />
            </StackPanel>
            <StackPanel Height="30" Orientation="Horizontal" Margin="10">
                <TextBlock Text="Settings:   " VerticalAlignment="Center"/>
                <Button x:Name="btnClear" Content="Clear" Click="btnClear_Click" />
                <Button x:Name="btnCount" Content="Count" Click="btnCount_Click" />
                <Button x:Name="btnKeys" Content="Get Keys" Click="btnKeys_Click" />
                <Button x:Name="btnValues" Content="Get Values" Click="btnValues_Click" />
            </StackPanel>
            <StackPanel Height="30" Orientation="Horizontal" Margin="10">
                <TextBlock Text="Results:    " VerticalAlignment="Center"/>
                <TextBox x:Name="tbResults" Width="230" Margin="0,0,5,0"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</UserControl>

Visual Basic

Imports System.IO.IsolatedStorage

Partial Public Class Page
    Inherits UserControl
    Private userSettings As IsolatedStorageSettings = IsolatedStorageSettings.ApplicationSettings

    Public Sub New()
        InitializeComponent()
        ' Retrieve and set user name.
        Try
            Dim name As String = CType(userSettings("name"), String)
            tbGreeting.Text = "Hello, " & name
        Catch ex As System.Collections.Generic.KeyNotFoundException
            ' No preference is saved.
            tbGreeting.Text = "Hello, World"
        End Try
    End Sub

    Private Sub btnAddName_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
        Try
            userSettings.Add("name", tbName.Text)
            tbResults.Text = "Name saved. Refresh page to see changes."
        Catch ex As ArgumentException
            tbResults.Text = ex.Message
        End Try
    End Sub

    Private Sub btnChangeName_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
        userSettings("name") = tbName.Text
        tbResults.Text = "Name changed. Refresh page to see changes."
    End Sub

    Private Sub btnRemoveName_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
        If userSettings.Remove("name") = True Then
            tbResults.Text = "Name removed. Refresh page to see changes."
        Else
            tbResults.Text = "Name could not be removed. Key does not exist."
        End If
    End Sub

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
        userSettings.Clear()
        tbResults.Text = "Settings cleared. Refresh page to see changes."
    End Sub

    Private Sub btnCount_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
        tbResults.Text = "Count: " & userSettings.Count()
    End Sub

    Private Sub btnKeys_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
        Dim sb As System.Text.StringBuilder = New System.Text.StringBuilder("Keys: ")

        For Each k As String In userSettings.Keys
            sb.Append(k & "; ")
        Next
        tbResults.Text = sb.ToString
    End Sub

    Private Sub btnValues_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
        Dim sb As System.Text.StringBuilder = New System.Text.StringBuilder("Values: ")

        For Each v As Object In userSettings.Values
            sb.Append(v.ToString() & "; ")
        Next
        tbResults.Text = sb.ToString
    End Sub
End Class

using System;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.IO.IsolatedStorage;

namespace IsolatedStorageSample
{
    public partial class Page : UserControl
    {
        private IsolatedStorageSettings userSettings = IsolatedStorageSettings.ApplicationSettings;

        public Page()
        {
            InitializeComponent();

            // Retrieve and set user name.
            try
            {
                string name = (string)userSettings["name"];
                tbGreeting.Text = "Hello, " + name;
            }
            catch (System.Collections.Generic.KeyNotFoundException)
            {
                // No preference is saved.
                tbGreeting.Text = "Hello, World";
            }
        }

        private void btnAddName_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                userSettings.Add("name", tbName.Text);
                tbResults.Text = "Name saved. Refresh page to see changes.";
            }
            catch (ArgumentException ex)
            {
                tbResults.Text = ex.Message;
            }
        }

        private void btnChangeName_Click(object sender, RoutedEventArgs e)
        {
            userSettings["name"] = tbName.Text;
            tbResults.Text = "Name changed. Refresh page to see changes.";
        }

        private void btnRemoveName_Click(object sender, RoutedEventArgs e)
        {
            if (userSettings.Remove("name") == true)
            {
                tbResults.Text = "Name removed. Refresh page to see changes.";
            }
            else
            {
                tbResults.Text = "Name could not be removed. Key does not exist.";
            }

        }

        private void btnClear_Click(object sender, RoutedEventArgs e)
        {
            userSettings.Clear();
            tbResults.Text = "Settings cleared. Refresh page to see changes.";
        }

        private void btnCount_Click(object sender, RoutedEventArgs e)
        {
            tbResults.Text = "Count: " + userSettings.Count();
        }

        private void btnKeys_Click(object sender, RoutedEventArgs e)
        {
            System.Text.StringBuilder sb = new System.Text.StringBuilder("Keys: ");

            foreach (string k in userSettings.Keys)
            {
                sb.Append(k + "; ");
            }
            tbResults.Text = sb.ToString();
        }

        private void btnValues_Click(object sender, RoutedEventArgs e)
        {
            System.Text.StringBuilder sb = new System.Text.StringBuilder("Values: ");

            foreach (Object v in userSettings.Values)
            {
                sb.Append(v.ToString() + "; ");
            }
            tbResults.Text = sb.ToString();
        }
    }
}

Inheritance Hierarchy

System..::.Object
System.IO.IsolatedStorage..::.IsolatedStorageSettings

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Reference

IsolatedStorageSettings Members

System.IO.IsolatedStorage Namespace

IsolatedStorageFile

GetUserStoreForApplication

GetUserStoreForSite

Other Resources

How to: Store and Retrieve Application Settings Using Isolated Storage