Represents an isolated storage area containing files and directories.
(in mscorlib.dll)
Visual Basic (Declaration)
Public NotInheritable Class IsolatedStorageFile _
Implements IDisposable
Dim instance As IsolatedStorageFile
public sealed class IsolatedStorageFile : IDisposable
This class abstracts the virtual file system for isolated storage. An IsolatedStorageFile object corresponds to a specific isolated storage scope, where files represented by IsolatedStorageFileStream objects exist. Applications can use isolated storage to save data in their own isolated portion of the file system, without having to specify a particular path within the file system.
The root of the virtual file system is located in a per-user, obfuscated folder on the physical file system. Each unique identifier provided by the host maps to a different root, which gives each application its own virtual file system. An application cannot navigate out of its own file system into another.
Since isolated stores are scoped to particular assemblies, most other managed code will not be able to access your code's data (highly trusted managed code and administration tools can access stores from other assemblies). Unmanaged code can access any isolated stores.
The following example shows how to use an IsolatedStorageFile object for most I/O tasks.
Imports System
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Input
Imports System.IO
Imports System.IO.IsolatedStorage
Imports System.Collections
Imports System.Text
Class Example
Public Shared Sub Demo(ByVal outputBlock As TextBlock)
' Obtain an isolated store for an application.
Try
Using store As IsolatedStorageFile = _
IsolatedStorageFile.GetUserStoreForApplication()
' Use a StringBuilder to construct output.
Dim sb As StringBuilder = New StringBuilder
' Create three directories in the root.
store.CreateDirectory("MyApp1")
store.CreateDirectory("MyApp2")
store.CreateDirectory("MyApp3")
' Create three subdirectories under MyApp1.
Dim subdirectory1 As String = Path.Combine("MyApp1", "SubDir1")
Dim subdirectory2 As String = Path.Combine("MyApp1", "SubDir2")
Dim subdirectory3 As String = Path.Combine("MyApp1", "SubDir3")
store.CreateDirectory(subdirectory1)
store.CreateDirectory(subdirectory2)
store.CreateDirectory(subdirectory3)
' Create a file in the root.
Dim rootFile As IsolatedStorageFileStream = _
store.CreateFile("InTheRoot.txt")
rootFile.Close()
' Create a file in a subdirectory.
Dim subDirFile As IsolatedStorageFileStream = _
store.CreateFile(Path.Combine(subdirectory1, "MyApp1A.txt"))
subDirFile.Close()
' Gather file information.
Dim directoriesInTheRoot() As String = store.GetDirectoryNames
Dim filesInTheRoot() As String = store.GetFileNames
Dim searchpath As String = Path.Combine(subdirectory1, "*.*")
Dim filesInSubDirs() As String = store.GetFileNames(searchpath)
' Find subdirectories within the MyApp1
' directory using the multi character '*' wildcard.
Dim subDirectories() As String = _
store.GetDirectoryNames(Path.Combine("MyApp1", "*"))
' List file infomration
' List the directories in the root.
sb.AppendLine("Directories in root:")
For Each dir As String In directoriesInTheRoot
sb.AppendLine((" - " + dir))
Next
sb.AppendLine()
' List the subdirectories under MyApp1.
sb.AppendLine("Directories under MyApp1:")
For Each sDir As String In subDirectories
sb.AppendLine((" - " + sDir))
Next
sb.AppendLine()
' List files in the root.
sb.AppendLine("Files in the root:")
For Each fileName As String In filesInTheRoot
sb.AppendLine((" - " + fileName))
Next
sb.AppendLine()
' List files in MyApp1\SubDir1.
sb.AppendLine("Files in MyApp1\SubDir1:")
For Each fileName As String In filesInSubDirs
sb.AppendLine((" - " + fileName))
Next
sb.AppendLine()
' Write to an existing file: MyApp1\SubDir1\MyApp1A.txt
' Determine if the file exists before writing to it.
Dim filePath As String = Path.Combine(subdirectory1, "MyApp1A.txt")
If store.FileExists(filePath) Then
Try
Using sw As StreamWriter = _
New StreamWriter(store.OpenFile(filePath, FileMode.Open, FileAccess.Write))
sw.WriteLine("To do list:")
sw.WriteLine("1. Buy supplies.")
End Using
Catch ex As IsolatedStorageException
sb.AppendLine(ex.Message)
End Try
Else
sb.AppendLine((filePath + "does not exist"))
End If
' Read the contents of the file: MyApp1\SubDir1\MyApp1A.txt
Try
Using reader As StreamReader = _
New StreamReader(store.OpenFile(filePath, FileMode.Open, FileAccess.Read))
Dim contents As String = reader.ReadToEnd
sb.AppendLine(filePath + " contents:")
sb.AppendLine(contents)
End Using
Catch ex As IsolatedStorageException
sb.Append(ex.Message)
End Try
' Delete a file.
Try
If store.FileExists(filePath) Then
store.DeleteFile(filePath)
End If
Catch ex As IsolatedStorageException
sb.AppendLine(ex.Message)
End Try
' Delete a specific directory.
Dim dirDelete As String = Path.Combine("MyApp1", "SubDir3")
Try
If store.DirectoryExists(dirDelete) Then
store.DeleteDirectory(dirDelete)
End If
Catch ex As IsolatedStorageException
sb.AppendLine(ex.Message)
End Try
sb.AppendLine()
' remove the store
store.Remove()
sb.AppendLine("Store removed.")
outputBlock.Text = sb.ToString()
End Using
Catch Ex As IsolatedStorageException
' TODO: Handle that store was unable to be accessed.
End Try
End Sub
End Class
' Quota status in increase examples
Class StoreQuota
' Assumes an event handler for the MouseLeftbuttonUp
' event is defined for a control named 'IncreaseQuota'
' In the control's XAML: MouseLeftButtonUp="IncreaseQuota_OnLeftMouseButtonUp"
Public Sub IncreaseQuota_OnClick(ByVal sender As Object, ByVal e As MouseEventArgs)
' Obtain an isolated store for an application.
Try
Using store As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication()
' Request 5MB more space in bytes.
Dim spaceToAdd As Int64 = 5242880
Dim curAvail As Int64 = store.AvailableFreeSpace
' If available space is less than
' what is requested, try to increase.
If (curAvail < spaceToAdd) Then
' Request more quota space.
If Not store.IncreaseQuotaTo((store.Quota + spaceToAdd)) Then
' The user clicked NO to the
' host's prompt to approve the quota increase.
Else
' The user clicked YES to the
' host's prompt to approve the quota increase.
End If
End If
End Using
Catch Ex As IsolatedStorageException
' TODO: Handle that store could not be accessed.
End Try
End Sub
Public Shared Sub ShowIsoStoreStatus(ByVal inputBlock As TextBlock)
' Obtain an isolated store for an application.
Try
Using store As IsolatedStorageFile = _
IsolatedStorageFile.GetUserStoreForApplication()
Dim spaceUsed As String = (store.Quota - store.AvailableFreeSpace).ToString
Dim spaceAvailable As String = store.AvailableFreeSpace.ToString
Dim curQuota As String = store.Quota.ToString
inputBlock.Text = String.Format("Quota: {0} bytes, Used: {1} bytes, Available: {2} bytes", _
curQuota, spaceUsed, spaceAvailable)
End Using
Catch Ex As IsolatedStorageException
inputBlock.Text = "Unable to access store."
End Try
End Sub
End Class
' This example's Example.Demo method
' produces the following output:
' -----
' Directories in root:
' - MyApp1
' - MyApp2
' - MyApp3
' Directories under MyApp1:
' - SubDir1
' - SubDir2
' - SubDir3
' Files in the root:
' - InTheRoot.txt
' Files in MyApp1\SubDir1:
' - MyApp1A.txt
' MyApp1\SubDir1\MyApp1A.txt contents:
' To do list:
' 1. Buy supplies.
' Store removed.
' -----
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.IO;
using System.IO.IsolatedStorage;
using System.Collections;
using System.Text;
class Example
{
public static void Demo(TextBlock outputBlock)
{
// Obtain an isolated store for an application.
try
{
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
// Use a StringBuilder to construct output.
StringBuilder sb = new StringBuilder();
// Create three directories in the root.
store.CreateDirectory("MyApp1");
store.CreateDirectory("MyApp2");
store.CreateDirectory("MyApp3");
// Create three subdirectories under MyApp1.
string subdirectory1 = Path.Combine("MyApp1", "SubDir1");
string subdirectory2 = Path.Combine("MyApp1", "SubDir2");
string subdirectory3 = Path.Combine("MyApp1", "SubDir3");
store.CreateDirectory(subdirectory1);
store.CreateDirectory(subdirectory2);
store.CreateDirectory(subdirectory3);
// Create a file in the root.
IsolatedStorageFileStream rootFile = store.CreateFile("InTheRoot.txt");
rootFile.Close();
// Create a file in a subdirectory.
IsolatedStorageFileStream subDirFile =
store.CreateFile(Path.Combine(subdirectory1, "MyApp1A.txt"));
subDirFile.Close();
// Gather file information
string[] directoriesInTheRoot = store.GetDirectoryNames();
string[] filesInTheRoot = store.GetFileNames();
string searchpath = Path.Combine(subdirectory1, "*.*");
string[] filesInSubDirs = store.GetFileNames(searchpath);
// Find subdirectories within the MyApp1
// directory using the multi character '*' wildcard.
string[] subDirectories =
store.GetDirectoryNames(Path.Combine("MyApp1", "*"));
// List file information
// List the directories in the root.
sb.AppendLine("Directories in root:");
foreach (string dir in directoriesInTheRoot)
{
sb.AppendLine(" - " + dir);
}
sb.AppendLine();
// List the subdirectories under MyApp1.
sb.AppendLine("Directories under MyApp1:");
foreach (string sDir in subDirectories)
{
sb.AppendLine(" - " + sDir);
}
sb.AppendLine();
// List files in the root.
sb.AppendLine("Files in the root:");
foreach (string fileName in filesInTheRoot)
{
sb.AppendLine(" - " + fileName);
}
sb.AppendLine();
// List files in MyApp1\SubDir1.
sb.AppendLine(@"Files in MyApp1\SubDir1:");
foreach (string fileName in filesInSubDirs)
{
sb.AppendLine(" - " + fileName);
}
sb.AppendLine();
// Write to an existing file: MyApp1\SubDir1\MyApp1A.txt
// Determine if the file exists before writing to it.
string filePath = Path.Combine(subdirectory1, "MyApp1A.txt");
if (store.FileExists(filePath))
{
try
{
using (StreamWriter sw =
new StreamWriter(store.OpenFile(filePath,
FileMode.Open, FileAccess.Write)))
{
sw.WriteLine("To do list:");
sw.WriteLine("1. Buy supplies.");
}
}
catch (IsolatedStorageException ex)
{
sb.AppendLine(ex.Message);
}
}
// Read the contents of the file: MyApp1\SubDir1\MyApp1A.txt
try
{
using (StreamReader reader =
new StreamReader(store.OpenFile(filePath,
FileMode.Open, FileAccess.Read)))
{
string contents = reader.ReadToEnd();
sb.AppendLine(filePath + " contents:");
sb.AppendLine(contents);
}
}
catch (IsolatedStorageException ex)
{
sb.AppendLine(ex.Message);
}
// Delete a file.
try
{
if (store.FileExists(filePath))
{
store.DeleteFile(filePath);
}
}
catch (IsolatedStorageException ex)
{
sb.AppendLine(ex.Message);
}
// Delete a specific directory.
string dirDelete = Path.Combine("MyApp1", "SubDir3");
try
{
if (store.DirectoryExists(dirDelete))
{
store.DeleteDirectory(dirDelete);
}
}
catch (IsolatedStorageException ex)
{
sb.AppendLine(ex.Message);
}
sb.AppendLine();
// remove the store
store.Remove();
sb.AppendLine("Store removed.");
outputBlock.Text = sb.ToString();
}
}
catch (IsolatedStorageException)
{
// TODO: Handle that store was unable to be accessed.
}
}
}
// Quota status and increase quota examples
class StoreQuota
{
// Assumes an event handler for the MouseLeftbuttonUp
// event is defined for a control named 'IncreaseQuota'
// In the control's XAML: MouseLeftButtonUp="IncreaseQuota_OnLeftMouseButtonUp"
// User first selects UI to increase the quota.
public void IncreaseQuota_OnClick(object sender, MouseEventArgs e)
{
// Obtain an isolated store for an application.
try
{
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
// Request 5MB more space in bytes.
Int64 spaceToAdd = 5242880;
Int64 curAvail = store.AvailableFreeSpace;
// If available space is less than
// what is requested, try to increase.
if (curAvail < spaceToAdd)
{
// Request more quota space.
if (!store.IncreaseQuotaTo(store.Quota + spaceToAdd))
{
// The user clicked NO to the
// host's prompt to approve the quota increase.
}
else
{
// The user clicked YES to the
// host's prompt to approve the quota increase.
}
}
}
}
catch (IsolatedStorageException)
{
// TODO: Handle that store could not be accessed.
}
}
public static void ShowIsoStoreStatus(TextBlock inputBlock)
{
// Obtain an isolated store for an application.
try
{
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
string spaceUsed = (store.Quota - store.AvailableFreeSpace).ToString();
string spaceAvailable = store.AvailableFreeSpace.ToString();
string curQuota = store.Quota.ToString();
inputBlock.Text =
String.Format("Quota: {0} bytes, Used: {1} bytes, Available: {2} bytes",
curQuota, spaceUsed, spaceAvailable);
}
}
catch (IsolatedStorageException)
{
inputBlock.Text = "Unable to access store.";
}
}
}
// This example's Example.Demo method
// produces the following output:
// -----
// Directories in root:
// - MyApp1
// - MyApp2
// - MyApp3
// Directories under MyApp1:
// - SubDir1
// - SubDir2
// - SubDir3
// Files in the root:
// - InTheRoot.txt
// Files in MyApp1\SubDir1:
// - MyApp1A.txt
// MyApp1\SubDir1\MyApp1A.txt contents:
// To do list:
// 1. Buy supplies.
// Store removed.
// -----
System..::.Object
System.IO.IsolatedStorage..::.IsolatedStorageFile
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
Reference