IsolatedStorageFileStream Class

Definition

Exposes a file within isolated storage.

[System.Runtime.InteropServices.ComVisible(true)]
public class IsolatedStorageFileStream : System.IO.FileStream
Inheritance
IsolatedStorageFileStream
Attributes

Examples

The following console application demonstrates how you can use IsolatedStorageFile and IsolatedStorageFileStream to write data to an Isolated Storage file. The user is requested to log in. If the user is a new user, a News URL and a Sports URL are recorded as personal preferences in Isolated Storage. If the user is a returning user, the user's current preferences are displayed. The code examples used throughout this namespace are presented in the context of this sample application. You can use the Storeadm.exe (Isolated Storage Tool) utility to list and remove the Isolated Storage files that are created with this console application.

// This sample demonstrates methods of classes found in the System.IO IsolatedStorage namespace.
using namespace System;
using namespace System::IO;
using namespace System::IO::IsolatedStorage;
using namespace System::Security::Policy;
using namespace System::Security::Permissions;

public ref class LoginPrefs
{
private:
   String^ userName;
   String^ newsUrl;
   String^ sportsUrl;
   bool newPrefs;

public:

   [SecurityPermissionAttribute(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
   bool GetPrefsForUser()
   {
      try
      {
         
         // Retrieve an IsolatedStorageFile for the current Domain and Assembly.
         IsolatedStorageFile^ isoFile = IsolatedStorageFile::GetStore( static_cast<IsolatedStorageScope>(IsolatedStorageScope::User | IsolatedStorageScope::Assembly | IsolatedStorageScope::Domain), (Type^)nullptr, nullptr );
         IsolatedStorageFileStream^ isoStream = gcnew IsolatedStorageFileStream( this->userName,FileMode::Open,FileAccess::ReadWrite,isoFile );
         
         // farThe code executes to this point only if a file corresponding to the username exists.
         // Though you can perform operations on the stream, you cannot get a handle to the file.
         try
         {
            IntPtr aFileHandle = isoStream->Handle;
            Console::WriteLine( "A pointer to a file handle has been obtained. {0} {1}", aFileHandle, aFileHandle.GetHashCode() );
         }
         catch ( Exception^ e ) 
         {
            
            // Handle the exception.
            Console::WriteLine( "Expected exception" );
            Console::WriteLine( e->ToString() );
         }

         StreamReader^ reader = gcnew StreamReader( isoStream );
         
         // Read the data.
         this->NewsUrl = reader->ReadLine();
         this->SportsUrl = reader->ReadLine();
         reader->Close();
         isoFile->Close();
         isoStream->Close();
         return false;
      }
      catch ( Exception^ e ) 
      {
         
         // Expected exception if a file cannot be found. This indicates that we have a new user.
         String^ errorMessage = e->ToString();
         return true;
      }

   }


   bool GetIsoStoreInfo()
   {
      
      // Get a User store with type evidence for the current Domain and the Assembly.
      IsolatedStorageFile^ isoFile = IsolatedStorageFile::GetStore( static_cast<IsolatedStorageScope>(IsolatedStorageScope::User | IsolatedStorageScope::Assembly | IsolatedStorageScope::Domain), System::Security::Policy::Url::typeid, System::Security::Policy::Url::typeid );
      
      array<String^>^dirNames = isoFile->GetDirectoryNames( "*" );
      array<String^>^fileNames = isoFile->GetFileNames( "*" );
      
      // List directories currently in this Isolated Storage.
      if ( dirNames->Length > 0 )
      {
         for ( int i = 0; i < dirNames->Length; ++i )
         {
            Console::WriteLine( "Directory Name: {0}", dirNames[ i ] );

         }
      }

      
      // List the files currently in this Isolated Storage.
      // The list represents all users who have personal preferences stored for this application.
      if ( fileNames->Length > 0 )
      {
         for ( int i = 0; i < fileNames->Length; ++i )
         {
            Console::WriteLine( "File Name: {0}", fileNames[ i ] );

         }
      }

      
      isoFile->Close();
      return true;
   }


   double SetPrefsForUser()
   {
      try
      {
         
         IsolatedStorageFile^ isoFile;
         isoFile = IsolatedStorageFile::GetUserStoreForDomain();
         
         // Open or create a writable file.
         IsolatedStorageFileStream^ isoStream = gcnew IsolatedStorageFileStream( this->userName,FileMode::OpenOrCreate,FileAccess::Write,isoFile );
         StreamWriter^ writer = gcnew StreamWriter( isoStream );
         writer->WriteLine( this->NewsUrl );
         writer->WriteLine( this->SportsUrl );
         
         // Calculate the amount of space used to record the user's preferences.
         double d = isoFile->CurrentSize / isoFile->MaximumSize;
         Console::WriteLine( "CurrentSize = {0}", isoFile->CurrentSize.ToString() );
         Console::WriteLine( "MaximumSize = {0}", isoFile->MaximumSize.ToString() );
         writer->Close();
         isoFile->Close();
         isoStream->Close();
         return d;
         
      }
      catch ( Exception^ e ) 
      {      
         // Add code here to handle the exception.
         Console::WriteLine( e->ToString() );
         return 0.0;
      }

   }


   void DeleteFiles()
   {
      
      try
      {
         IsolatedStorageFile^ isoFile = IsolatedStorageFile::GetStore( static_cast<IsolatedStorageScope>(IsolatedStorageScope::User | IsolatedStorageScope::Assembly | IsolatedStorageScope::Domain), System::Security::Policy::Url::typeid, System::Security::Policy::Url::typeid );
         array<String^>^dirNames = isoFile->GetDirectoryNames( "*" );
         array<String^>^fileNames = isoFile->GetFileNames( "*" );
         
         // List the files currently in this Isolated Storage.
         // The list represents all users who have personal
         // preferences stored for this application.
         if ( fileNames->Length > 0 )
         {
            for ( int i = 0; i < fileNames->Length; ++i )
            {
               
               //Delete the files.
               isoFile->DeleteFile( fileNames[ i ] );

            }
            fileNames = isoFile->GetFileNames( "*" );
         }
         isoFile->Close();
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( e->ToString() );
      }

   }


   // This method deletes directories in the specified Isolated Storage, after first 
   // deleting the files they contain. In this example, the Archive directory is deleted. 
   // There should be no other directories in this Isolated Storage.
   void DeleteDirectories()
   {
      try
      {
         IsolatedStorageFile^ isoFile = IsolatedStorageFile::GetStore( static_cast<IsolatedStorageScope>(IsolatedStorageScope::User | IsolatedStorageScope::Assembly | IsolatedStorageScope::Domain), System::Security::Policy::Url::typeid, System::Security::Policy::Url::typeid );
         array<String^>^dirNames = isoFile->GetDirectoryNames( "*" );
         array<String^>^fileNames = isoFile->GetFileNames( "Archive\\*" );
         
         // Delete the current files within the Archive directory.
         if ( fileNames->Length > 0 )
         {
            for ( int i = 0; i < fileNames->Length; ++i )
            {
               
               //delete files
               isoFile->DeleteFile( String::Concat("Archive\\", fileNames[ i ]) );

            }
            fileNames = isoFile->GetFileNames( "Archive\\*" );
         }
         if ( dirNames->Length > 0 )
         {
            for ( int i = 0; i < dirNames->Length; ++i )
            {
               
               // Delete the Archive directory.
               isoFile->DeleteDirectory( dirNames[ i ] );

            }
         }
         dirNames = isoFile->GetDirectoryNames( "*" );
         isoFile->Remove();
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( e->ToString() );
      }

   }


   double SetNewPrefsForUser()
   {
      try
      {
         Byte inputChar;
         IsolatedStorageFile^ isoFile = IsolatedStorageFile::GetStore( static_cast<IsolatedStorageScope>(IsolatedStorageScope::User | IsolatedStorageScope::Assembly | IsolatedStorageScope::Domain), System::Security::Policy::Url::typeid, System::Security::Policy::Url::typeid );
         
         // If this is not a new user, archive the old preferences and 
         // overwrite them using the new preferences.
         if (  !this->NewPrefs )
         {
            if ( isoFile->GetDirectoryNames( "Archive" )->Length == 0 )
                        isoFile->CreateDirectory( "Archive" );
            else
            {
               
               // This is the stream to which data will be written.
               IsolatedStorageFileStream^ source = gcnew IsolatedStorageFileStream( this->userName,FileMode::OpenOrCreate,isoFile );
               
               // This is the stream from which data will be read.
               Console::WriteLine( "Is the source file readable?  {0}", (source->CanRead ? (String^)"true" : "false") );
               Console::WriteLine( "Creating new IsolatedStorageFileStream for Archive." );
               
               // Open or create a writable file.
               IsolatedStorageFileStream^ target = gcnew IsolatedStorageFileStream( String::Concat("Archive\\",this->userName),FileMode::OpenOrCreate,FileAccess::Write,FileShare::Write,isoFile );
               
               Console::WriteLine( "Is the target file writable? {0}", (target->CanWrite ? (String^)"true" : "false") );
               
               // Stream the old file to a new file in the Archive directory.
               if ( source->IsAsync && target->IsAsync )
               {
                  
                  // IsolatedStorageFileStreams cannot be asynchronous.  However, you
                  // can use the asynchronous BeginRead and BeginWrite functions
                  // with some possible performance penalty.
                  Console::WriteLine( "IsolatedStorageFileStreams cannot be asynchronous." );
               }
               else
               {
                  
                  Console::WriteLine( "Writing data to the new file." );
                  while ( source->Position < source->Length )
                  {
                     inputChar = (Byte)source->ReadByte();
                     target->WriteByte( (Byte)source->ReadByte() );
                  }
                  
                  // Determine the size of the IsolatedStorageFileStream
                  // by checking its Length property.
                  Console::WriteLine( "Total Bytes Read: {0}", source->Length.ToString() );
                  
               }
               
               // After you have read and written to the streams, close them.
               target->Close();
               source->Close();
            }
         }
         
         // Open or create a writable file, no larger than 10k
         IsolatedStorageFileStream^ isoStream = gcnew IsolatedStorageFileStream( this->userName,FileMode::OpenOrCreate,FileAccess::Write,FileShare::Write,10240,isoFile );
         
         isoStream->Position = 0; // Position to overwrite the old data.
         
         StreamWriter^ writer = gcnew StreamWriter( isoStream );
         
         // Update the data based on the new inputs.
         writer->WriteLine( this->NewsUrl );
         writer->WriteLine( this->SportsUrl );
         
         // Calculate the amount of space used to record this user's preferences.
         double d = isoFile->CurrentSize / isoFile->MaximumSize;
         Console::WriteLine( "CurrentSize = {0}", isoFile->CurrentSize.ToString() );
         Console::WriteLine( "MaximumSize = {0}", isoFile->MaximumSize.ToString() );
         
         // StreamWriter.Close implicitly closes isoStream.
         writer->Close();
         isoFile->Close();
         return d;
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( e->ToString() );
         return 0.0;
      }

   }

   LoginPrefs( String^ aUserName )
   {
      userName = aUserName;
      newPrefs = GetPrefsForUser();
   }


   property String^ NewsUrl 
   {
      String^ get()
      {
         return newsUrl;
      }

      void set( String^ value )
      {
         newsUrl = value;
      }

   }

   property String^ SportsUrl 
   {
      String^ get()
      {
         return sportsUrl;
      }

      void set( String^ value )
      {
         sportsUrl = value;
      }

   }

   property bool NewPrefs 
   {
      bool get()
      {
         return newPrefs;
      }

   }

};

void GatherInfoFromUser( LoginPrefs^ lp )
{
   Console::WriteLine( "Please enter the URL of your news site." );
   lp->NewsUrl = Console::ReadLine();
   Console::WriteLine( "Please enter the URL of your sports site." );
   lp->SportsUrl = Console::ReadLine();
}

int main()
{
   
   // Prompt the user for their username.
   Console::WriteLine( "Enter your login ID:" );
   
   // Does no error checking.
   LoginPrefs^ lp = gcnew LoginPrefs( Console::ReadLine() );
   if ( lp->NewPrefs )
   {
      Console::WriteLine( "Please set preferences for a new user." );
      GatherInfoFromUser( lp );
      
      // Write the new preferences to storage.
      double percentUsed = lp->SetPrefsForUser();
      Console::WriteLine( "Your preferences have been written. Current space used is {0}%", percentUsed );
   }
   else
   {
      Console::WriteLine( "Welcome back." );
      Console::WriteLine( "Your preferences have expired, please reset them." );
      GatherInfoFromUser( lp );
      lp->SetNewPrefsForUser();
      Console::WriteLine( "Your news site has been set to {0}\n and your sports site has been set to {1}.", lp->NewsUrl, lp->SportsUrl );
   }

   lp->GetIsoStoreInfo();
   Console::WriteLine( "Enter 'd' to delete the IsolatedStorage files and exit, or press any other key to exit without deleting files." );
   String^ consoleInput = Console::ReadLine();
   if ( consoleInput->Equals( "d" ) )
   {
      lp->DeleteFiles();
      lp->DeleteDirectories();
   }
}

// This sample demonstrates methods of classes found in the System.IO IsolatedStorage namespace.
using System;
using System.IO;
using System.IO.IsolatedStorage;
using System.Security.Policy;
using Microsoft.Win32.SafeHandles;
using System.Security.Permissions;

[assembly: CLSCompliantAttribute(true)]

class ConsoleApp
{
    [STAThread]
    static void Main(string[] args)
    {

        // Prompt the user for their username.

        Console.WriteLine("Login:");

        // Does no error checking.
        LoginPrefs lp = new LoginPrefs(Console.ReadLine());

        if (lp.NewPrefs)
        {
            Console.WriteLine("Please set preferences for a new user.");
            GatherInfoFromUser(lp);

            // Write the new preferences to storage.
            double percentUsed = lp.SetPrefsForUser();
            Console.WriteLine("Your preferences have been written. Current space used is " + percentUsed.ToString() + " %");
        }
        else
        {
            Console.WriteLine("Welcome back.");

            Console.WriteLine("Your preferences have expired, please reset them.");
            GatherInfoFromUser(lp);
            lp.SetNewPrefsForUser();

            Console.WriteLine("Your news site has been set to {0}\n and your sports site has been set to {1}.", lp.NewsUrl, lp.SportsUrl);
        }
        lp.GetIsoStoreInfo();
        Console.WriteLine("Enter 'd' to delete the IsolatedStorage files and exit, or press any other key to exit without deleting files.");
        string consoleInput = Console.ReadLine();
        if (consoleInput.ToLower() == "d")
        {
            lp.DeleteFiles();
            lp.DeleteDirectories();
        }

    }

    static void GatherInfoFromUser(LoginPrefs lp)
    {
        Console.WriteLine("Please enter the URL of your news site.");
        lp.NewsUrl = Console.ReadLine();
        Console.WriteLine("Please enter the URL of your sports site.");
        lp.SportsUrl = Console.ReadLine();
    }
}
[SecurityPermissionAttribute(SecurityAction.Demand, Flags=SecurityPermissionFlag.UnmanagedCode)]
public class LoginPrefs
{
    public LoginPrefs(string myUserName)
    {
        userName = myUserName;
        myNewPrefs = GetPrefsForUser();
    }
    string userName;

    string myNewsUrl;
    public string NewsUrl
    {
        get { return myNewsUrl; }
        set { myNewsUrl = value; }
    }

    string mySportsUrl;
    public string SportsUrl
    {
        get { return mySportsUrl; }
        set { mySportsUrl = value; }
    }
    bool myNewPrefs;
    public bool NewPrefs
    {
        get { return myNewPrefs; }
    }

    private bool GetPrefsForUser()
    {
        try
        {

            // Retrieve an IsolatedStorageFile for the current Domain and Assembly.
            IsolatedStorageFile isoFile =
                IsolatedStorageFile.GetStore(IsolatedStorageScope.User |
                IsolatedStorageScope.Assembly |
                IsolatedStorageScope.Domain,
                null,
                null);

            IsolatedStorageFileStream isoStream =
                new IsolatedStorageFileStream("substituteUsername",
                System.IO.FileMode.Open,
                System.IO.FileAccess.Read,
                 System.IO.FileShare.Read);

            // The code executes to this point only if a file corresponding to the username exists.
            // Though you can perform operations on the stream, you cannot get a handle to the file.

            try
            {

                SafeFileHandle aFileHandle = isoStream.SafeFileHandle;
                Console.WriteLine("A pointer to a file handle has been obtained. "
                    + aFileHandle.ToString() + " "
                    + aFileHandle.GetHashCode());
            }

            catch (Exception e)
            {
                // Handle the exception.
                Console.WriteLine("Expected exception");
                Console.WriteLine(e);
            }

            StreamReader reader = new StreamReader(isoStream);
            // Read the data.
            this.NewsUrl = reader.ReadLine();
            this.SportsUrl = reader.ReadLine();
            reader.Close();
            isoFile.Close();
            return false;
        }
        catch (System.IO.FileNotFoundException)
        {
            // Expected exception if a file cannot be found. This indicates that we have a new user.
            return true;
        }
    }
    public bool GetIsoStoreInfo()
    {
        // Get a User store with type evidence for the current Domain and the Assembly.
        IsolatedStorageFile isoFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User |
            IsolatedStorageScope.Assembly |
            IsolatedStorageScope.Domain,
            typeof(System.Security.Policy.Url),
            typeof(System.Security.Policy.Url));

        String[] dirNames = isoFile.GetDirectoryNames("*");
        String[] fileNames = isoFile.GetFileNames("*");

        // List directories currently in this Isolated Storage.
        if (dirNames.Length > 0)
        {
            for (int i = 0; i < dirNames.Length; ++i)
            {
                Console.WriteLine("Directory Name: " + dirNames[i]);
            }
        }

        // List the files currently in this Isolated Storage.
        // The list represents all users who have personal preferences stored for this application.
        if (fileNames.Length > 0)
        {
            for (int i = 0; i < fileNames.Length; ++i)
            {
                Console.WriteLine("File Name: " + fileNames[i]);
            }
        }

        isoFile.Close();
        return true;
    }

    public double SetPrefsForUser()
    {
        try
        {
            IsolatedStorageFile isoFile;
            isoFile = IsolatedStorageFile.GetUserStoreForDomain();

            // Open or create a writable file.
            IsolatedStorageFileStream isoStream =
                new IsolatedStorageFileStream(this.userName,
                FileMode.OpenOrCreate,
                FileAccess.Write,
                isoFile);

            StreamWriter writer = new StreamWriter(isoStream);
            writer.WriteLine(this.NewsUrl);
            writer.WriteLine(this.SportsUrl);
            // Calculate the amount of space used to record the user's preferences.
            double d = isoFile.CurrentSize / isoFile.MaximumSize;
            Console.WriteLine("CurrentSize = " + isoFile.CurrentSize.ToString());
            Console.WriteLine("MaximumSize = " + isoFile.MaximumSize.ToString());
            // StreamWriter.Close implicitly closes isoStream.
            writer.Close();
            isoFile.Dispose();
            isoFile.Close();
            return d;
        }
        catch (IsolatedStorageException ex)
        {
            // Add code here to handle the exception.
            Console.WriteLine(ex);
            return 0.0;
        }
    }

    public void DeleteFiles()
    {
        try
        {
            IsolatedStorageFile isoFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User |
                IsolatedStorageScope.Assembly |
                IsolatedStorageScope.Domain,
                typeof(System.Security.Policy.Url),
                typeof(System.Security.Policy.Url));

            String[] dirNames = isoFile.GetDirectoryNames("*");
            String[] fileNames = isoFile.GetFileNames("*");

            // List the files currently in this Isolated Storage.
            // The list represents all users who have personal
            // preferences stored for this application.
            if (fileNames.Length > 0)
            {
                for (int i = 0; i < fileNames.Length; ++i)
                {
                    // Delete the files.
                    isoFile.DeleteFile(fileNames[i]);
                }
                // Confirm that no files remain.
                fileNames = isoFile.GetFileNames("*");
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }

    }
    // This method deletes directories in the specified Isolated Storage, after first 
    // deleting the files they contain. In this example, the Archive directory is deleted. 
    // There should be no other directories in this Isolated Storage.
    public void DeleteDirectories()
    {
        try
        {
            IsolatedStorageFile isoFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User |
                IsolatedStorageScope.Assembly |
                IsolatedStorageScope.Domain,
                typeof(System.Security.Policy.Url),
                typeof(System.Security.Policy.Url));
            String[] dirNames = isoFile.GetDirectoryNames("*");
            String[] fileNames = isoFile.GetFileNames("Archive\\*");

            // Delete all the files currently in the Archive directory.

            if (fileNames.Length > 0)
            {
                for (int i = 0; i < fileNames.Length; ++i)
                {
                    // Delete the files.
                    isoFile.DeleteFile("Archive\\" + fileNames[i]);
                }
                // Confirm that no files remain.
                fileNames = isoFile.GetFileNames("Archive\\*");
            }


            if (dirNames.Length > 0)
            {
                for (int i = 0; i < dirNames.Length; ++i)
                {
                    // Delete the Archive directory.
                }
            }
            dirNames = isoFile.GetDirectoryNames("*");
            isoFile.Remove();
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }
    public double SetNewPrefsForUser()
    {
        try
        {
            byte inputChar;
            IsolatedStorageFile isoFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User |
                IsolatedStorageScope.Assembly |
                IsolatedStorageScope.Domain,
                typeof(System.Security.Policy.Url),
                typeof(System.Security.Policy.Url));

            // If this is not a new user, archive the old preferences and 
            // overwrite them using the new preferences.
            if (!this.myNewPrefs)
            {
                if (isoFile.GetDirectoryNames("Archive").Length == 0)
                    isoFile.CreateDirectory("Archive");
                else
                {

                    IsolatedStorageFileStream source =
                        new IsolatedStorageFileStream(this.userName, FileMode.OpenOrCreate,
                        isoFile);
                    // This is the stream from which data will be read.
                    Console.WriteLine("Is the source file readable? " + (source.CanRead ? "true" : "false"));
                    Console.WriteLine("Creating new IsolatedStorageFileStream for Archive.");

                    // Open or create a writable file.
                    IsolatedStorageFileStream target =
                        new IsolatedStorageFileStream("Archive\\ " + this.userName,
                        FileMode.OpenOrCreate,
                        FileAccess.Write,
                        FileShare.Write,
                        isoFile);
                    Console.WriteLine("Is the target file writable? " + (target.CanWrite ? "true" : "false"));
                    // Stream the old file to a new file in the Archive directory.
                    if (source.IsAsync && target.IsAsync)
                    {
                        // IsolatedStorageFileStreams cannot be asynchronous.  However, you
                        // can use the asynchronous BeginRead and BeginWrite functions
                        // with some possible performance penalty.

                        Console.WriteLine("IsolatedStorageFileStreams cannot be asynchronous.");
                    }

                    else
                    {
                        Console.WriteLine("Writing data to the new file.");
                        while (source.Position < source.Length)
                        {
                            inputChar = (byte)source.ReadByte();
                            target.WriteByte(inputChar);
                        }

                        // Determine the size of the IsolatedStorageFileStream
                        // by checking its Length property.
                        Console.WriteLine("Total Bytes Read: " + source.Length);

                    }

                    // After you have read and written to the streams, close them.
                    target.Close();
                    source.Close();
                }
            }

            // Open or create a writable file with a maximum size of 10K.
            IsolatedStorageFileStream isoStream =
                new IsolatedStorageFileStream(this.userName,
                FileMode.OpenOrCreate,
                FileAccess.Write,
                FileShare.Write,
                10240,
                isoFile);
            isoStream.Position = 0;  // Position to overwrite the old data.
            StreamWriter writer = new StreamWriter(isoStream);
            // Update the data based on the new inputs.
            writer.WriteLine(this.NewsUrl);
            writer.WriteLine(this.SportsUrl);

            // Calculate the amount of space used to record this user's preferences.
            double d = isoFile.CurrentSize / isoFile.MaximumSize;
            Console.WriteLine("CurrentSize = " + isoFile.CurrentSize.ToString());
            Console.WriteLine("MaximumSize = " + isoFile.MaximumSize.ToString());
            // StreamWriter.Close implicitly closes isoStream.
            writer.Close();
            isoFile.Close();

            return d;
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
            return 0.0;
        }
    }
}

'This sample demonstrates methods of classes found in the System.IO IsolatedStorage namespace.
Imports System
Imports System.IO
Imports System.IO.IsolatedStorage
Imports System.Security.Policy
Imports Microsoft.VisualBasic
Imports Microsoft.Win32.SafeHandles
Imports System.Security.Permissions



Namespace ISOCS
    _
    Class ConsoleApp


        <STAThread()> _
       Overloads Shared Sub Main(ByVal args() As String)

            ' Prompt the user for their username.
            Console.WriteLine("Enter your login ID:")

            ' Does no error checking.
            Dim lp As New LoginPrefs(Console.ReadLine())

            If lp.NewPrefs Then
                Console.WriteLine("Please set preferences for a new user.")
                GatherInfoFromUser(lp)

                ' Write the new preferences to storage.
                Dim percentUsed As Double = lp.SetPrefsForUser()
                Console.WriteLine(("Your preferences have been written. Current space used is " & percentUsed.ToString() & " %"))
            Else
                Console.WriteLine("Welcome back.")

                Console.WriteLine("Your preferences have expired, please reset them.")
                GatherInfoFromUser(lp)
                lp.SetNewPrefsForUser()

                Console.WriteLine("Your news site has been set to {0}" & ControlChars.Cr & " and your sports site has been set to {1}.", lp.NewsUrl, lp.SportsUrl)
            End If
            lp.GetIsoStoreInfo()
            Console.WriteLine("Enter 'd' to delete the IsolatedStorage files and exit, or press any other key to exit without deleting files.")
            Dim consoleInput As String = Console.ReadLine()
            If consoleInput.ToLower() = "d" Then
                lp.DeleteFiles()
                lp.DeleteDirectories()
            End If
        End Sub 'Main


        Shared Sub GatherInfoFromUser(ByVal lp As LoginPrefs)
            Console.WriteLine("Please enter the URL of your news site.")
            lp.NewsUrl = Console.ReadLine()
            Console.WriteLine("Please enter the URL of your sports site.")
            lp.SportsUrl = Console.ReadLine()
        End Sub 'GatherInfoFromUser
    End Class 'ConsoleApp
    _

    <SecurityPermissionAttribute(SecurityAction.Demand, Flags:=SecurityPermissionFlag.UnmanagedCode)> _
    Public Class LoginPrefs

        Public Sub New(ByVal myUserName As String)
            userName = myUserName
            myNewPrefs = GetPrefsForUser()
        End Sub 'New
        Private userName As String

        Private myNewsUrl As String

        Public Property NewsUrl() As String
            Get
                Return myNewsUrl
            End Get
            Set(ByVal Value As String)
                myNewsUrl = Value
            End Set
        End Property
        Private mySportsUrl As String

        Public Property SportsUrl() As String
            Get
                Return mySportsUrl
            End Get
            Set(ByVal Value As String)
                mySportsUrl = Value
            End Set
        End Property
        Private myNewPrefs As Boolean

        Public ReadOnly Property NewPrefs() As Boolean
            Get
                Return myNewPrefs
            End Get
        End Property

        Private Function GetPrefsForUser() As Boolean
            Try
                ' Retrieve an IsolatedStorageFile for the current Domain and Assembly.
                Dim isoFile As IsolatedStorageFile = _
                    IsolatedStorageFile.GetStore(IsolatedStorageScope.User _
                    Or IsolatedStorageScope.Assembly _
                    Or IsolatedStorageScope.Domain, Nothing, Nothing)

                Dim isoStream As New IsolatedStorageFileStream("substituteUsername", System.IO.FileMode.Open, _
                    System.IO.FileAccess.Read, System.IO.FileShare.Read)
                ' farThe code executes to this point only if a file corresponding to the username exists.
                ' Though you can perform operations on the stream, you cannot get a handle to the file.
                Try

                    Dim aFileHandle As SafeFileHandle = isoStream.SafeFileHandle
                    Console.WriteLine(("A pointer to a file handle has been obtained. " & aFileHandle.ToString() & " " & aFileHandle.GetHashCode()))

                Catch ex As Exception
                    ' Handle the exception.
                    Console.WriteLine("Expected exception")
                    Console.WriteLine(ex.ToString())
                End Try

                Dim reader As New StreamReader(isoStream)
                ' Read the data.
                Me.NewsUrl = reader.ReadLine()
                Me.SportsUrl = reader.ReadLine()
                reader.Close()
                isoFile.Close()
                Return False
            Catch ex As System.IO.FileNotFoundException
                ' Expected exception if a file cannot be found. This indicates that we have a new user.
                Return True
            End Try
        End Function 'GetPrefsForUser

        Public Function GetIsoStoreInfo() As Boolean
            Try
                'Get a User store with type evidence for the current Domain and the Assembly.
                Dim isoFile As IsolatedStorageFile = _
                    IsolatedStorageFile.GetStore(IsolatedStorageScope.User Or _
                    IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, _
                    GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))
                Dim dirNames As String() = isoFile.GetDirectoryNames("*")
                Dim fileNames As String() = isoFile.GetFileNames("*")
                Dim name As String

                ' List directories currently in this Isolated Storage.
                If dirNames.Length > 0 Then

                    For Each name In dirNames
                        Console.WriteLine("Directory Name: " & name)
                    Next name
                End If

                ' List the files currently in this Isolated Storage.
                ' The list represents all users who have personal preferences stored for this application.
                If fileNames.Length > 0 Then

                    For Each name In fileNames
                        Console.WriteLine("File Name: " & name)
                    Next name
                End If
                isoFile.Close()
                Return True
            Catch ex As Exception
                Console.WriteLine(ex.ToString())
            End Try
        End Function 'GetIsoStoreInfo

        Public Function SetPrefsForUser() As Double
            Try
                Dim isoFile As IsolatedStorageFile
                isoFile = IsolatedStorageFile.GetUserStoreForDomain()

                ' Open or create a writable file.
                Dim isoStream As New IsolatedStorageFileStream(Me.userName, FileMode.OpenOrCreate, _
                    FileAccess.Write, isoFile)

                Dim writer As New StreamWriter(isoStream)
                writer.WriteLine(Me.NewsUrl)
                writer.WriteLine(Me.SportsUrl)
                ' Calculate the amount of space used to record the user's preferences.
                Dim d As Double = Convert.ToDouble(isoFile.CurrentSize) / Convert.ToDouble(isoFile.MaximumSize)
                Console.WriteLine(("CurrentSize = " & isoFile.CurrentSize.ToString()))
                Console.WriteLine(("MaximumSize = " & isoFile.MaximumSize.ToString()))
                ' StreamWriter.Close implicitly closes isoStream.
                writer.Close()
                isoFile.Dispose()
                isoFile.Close()
                Return d
            Catch ex As Exception
                ' Add code here to handle the exception.
                Console.WriteLine(ex)
                Return 0.0
            End Try
        End Function 'SetPrefsForUser


        Public Sub DeleteFiles()
            Try
                Dim isoFile As IsolatedStorageFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User Or _
                    IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, _
                    GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))
                Dim name As String
                Dim dirNames As String() = isoFile.GetDirectoryNames("*")
                Dim fileNames As String() = isoFile.GetFileNames("*")
                ' List the files currently in this Isolated Storage.
                ' The list represents all users who have personal
                ' preferences stored for this application.
                If fileNames.Length > 0 Then
                    For Each name In fileNames
                        ' Delete the files.
                        isoFile.DeleteFile(name)
                    Next name
                    'Confirm no files are left.
                    fileNames = isoFile.GetFileNames("*")
                End If
            Catch ex As Exception
                Console.WriteLine(ex.ToString())
            End Try
        End Sub 'DeleteFiles

        ' This method deletes directories in the specified Isolated Storage, after first 
        ' deleting the files they contain. In this example, the Archive directory is deleted. 
        ' There should be no other directories in this Isolated Storage.
        Public Sub DeleteDirectories()
            Try
                Dim isoFile As IsolatedStorageFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User _
                    Or IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, _
                    GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))
                Dim name As String
                Dim dirNames As String() = isoFile.GetDirectoryNames("*")
                Dim fileNames As String() = isoFile.GetFileNames("Archive\*")
                ' Delete all the files currently in the Archive directory.
                If fileNames.Length > 0 Then
                    For Each name In fileNames
                        isoFile.DeleteFile(("Archive\" & name))
                    Next name
                    'Confirm no files are left.
                    fileNames = isoFile.GetFileNames("Archive\*")
                End If
                If dirNames.Length > 0 Then
                    For Each name In dirNames
                        ' Delete the Archive directory.
                        isoFile.DeleteDirectory(name)
                    Next name
                End If
                dirNames = isoFile.GetDirectoryNames("*")
                isoFile.Remove()
            Catch ex As Exception
                Console.WriteLine(ex.ToString())
            End Try
        End Sub 'DeleteDirectories

        Public Function SetNewPrefsForUser() As Double
            Try
                Dim inputChar As Byte
                Dim isoFile As IsolatedStorageFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User Or _
                    IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, _
                    GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))

                ' If this is not a new user, archive the old preferences and 
                ' overwrite them using the new preferences.
                If Not Me.myNewPrefs Then
                    If isoFile.GetDirectoryNames("Archive").Length = 0 Then
                        isoFile.CreateDirectory("Archive")
                    Else

                        Dim source As New IsolatedStorageFileStream(Me.userName, FileMode.OpenOrCreate, isoFile)
                        Dim canWrite, canRead As Boolean
                        ' This is the stream from which data will be read.
                        If source.CanRead Then canRead = True Else canRead = False
                        Console.WriteLine("Is the source file readable? " & canRead)
                        Console.WriteLine("Creating new IsolatedStorageFileStream for Archive.")
                        ' Open or create a writable file.
                        Dim target As New IsolatedStorageFileStream("Archive\ " & Me.userName, _
                             FileMode.OpenOrCreate, FileAccess.Write, FileShare.Write, isoFile)
                        ' This is the stream to which data will be written.
                        If target.CanWrite Then canWrite = True Else canWrite = False
                        Console.WriteLine("Is the target file writable? " & canWrite)
                        target.SetLength(0)  'rewind the target file

                        ' Stream the old file to a new file in the Archive directory.
                        If source.IsAsync And target.IsAsync Then
                            ' IsolatedStorageFileStreams cannot be asynchronous.  However, you
                            ' can use the asynchronous BeginRead and BeginWrite functions
                            ' with some possible performance penalty.
                            Console.WriteLine("IsolatedStorageFileStreams cannot be asynchronous.")
                        Else
                            Console.WriteLine("Writing data to the new file.")
                            While source.Position < source.Length
                                inputChar = CByte(source.ReadByte())
                                target.WriteByte(inputChar)
                            End While

                            ' Determine the size of the IsolatedStorageFileStream
                            ' by checking its Length property.
                            Console.WriteLine(("Total Bytes Read: " & source.Length))
                        End If

                        ' After you have read and written to the streams, close them.	
                        target.Close()
                        source.Close()
                    End If
                End If
                ' Open or create a writable file with a maximum size of 10K.
                Dim isoStream As New IsolatedStorageFileStream(Me.userName, FileMode.OpenOrCreate, _
                    FileAccess.Write, FileShare.Write, 10240, isoFile)
                isoStream.SetLength(0) 'Position to overwrite the old data.
                Dim writer As New StreamWriter(isoStream)
                ' Update the data based on the new inputs.
                writer.WriteLine(Me.NewsUrl)
                writer.WriteLine(Me.SportsUrl)

                '  Calculate the amount of space used to record this user's preferences.
                Dim d As Double = Convert.ToDouble(isoFile.CurrentSize) / Convert.ToDouble(isoFile.MaximumSize)
                Console.WriteLine(("CurrentSize = " & isoFile.CurrentSize.ToString()))
                Console.WriteLine(("MaximumSize = " & isoFile.MaximumSize.ToString()))
                ' StreamWriter.Close implicitly closes isoStream.
                writer.Close()
                isoFile.Close()

                Return d
            Catch ex As Exception
                Console.WriteLine(ex.ToString())
                Return 0.0
            End Try
        End Function 'SetNewPrefsForUser
    End Class 'LoginPrefs
End Namespace 'ISOCS

Remarks

Use this class to read, write and create files in isolated storage.

Since this class extends FileStream, you can use an instance of IsolatedStorageFileStream in most situations where a FileStream might otherwise be used, such as to construct a StreamReader or StreamWriter.

This type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the "Using an Object that Implements IDisposable" section in the IDisposable interface topic.

Important

Isolated storage is not available for Windows 8.x Store apps. Instead, use the application data classes in the Windows.Storage namespaces included in the Windows Runtime API to store local data and files. For more information, see Application data in the Windows Dev Center.

Constructors

IsolatedStorageFileStream(String, FileMode)

Initializes a new instance of an IsolatedStorageFileStream object giving access to the file designated by path in the specified mode.

IsolatedStorageFileStream(String, FileMode, FileAccess)

Initializes a new instance of the IsolatedStorageFileStream class giving access to the file designated by path, in the specified mode, with the kind of access requested.

IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare)

Initializes a new instance of the IsolatedStorageFileStream class giving access to the file designated by path, in the specified mode, with the specified file access, using the file sharing mode specified by share.

IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare, Int32)

Initializes a new instance of the IsolatedStorageFileStream class giving access to the file designated by path, in the specified mode, with the specified file access, using the file sharing mode specified by share, with the buffersize specified.

IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare, Int32, IsolatedStorageFile)

Initializes a new instance of the IsolatedStorageFileStream class giving access to the file designated by path, in the specified mode, with the specified file access, using the file sharing mode specified by share, with the buffersize specified, and in the context of the IsolatedStorageFile specified by isf.

IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare, IsolatedStorageFile)

Initializes a new instance of the IsolatedStorageFileStream class giving access to the file designated by path, in the specified mode, with the specified file access, using the file sharing mode specified by share, and in the context of the IsolatedStorageFile specified by isf.

IsolatedStorageFileStream(String, FileMode, FileAccess, IsolatedStorageFile)

Initializes a new instance of the IsolatedStorageFileStream class giving access to the file designated by path in the specified mode, with the specified file access, and in the context of the IsolatedStorageFile specified by isf.

IsolatedStorageFileStream(String, FileMode, IsolatedStorageFile)

Initializes a new instance of the IsolatedStorageFileStream class giving access to the file designated by path, in the specified mode, and in the context of the IsolatedStorageFile specified by isf.

Properties

CanRead

Gets a Boolean value indicating whether the file can be read.

CanSeek

Gets a Boolean value indicating whether seek operations are supported.

CanTimeout

Gets a value that determines whether the current stream can time out.

(Inherited from Stream)
CanWrite

Gets a Boolean value indicating whether you can write to the file.

Handle

Gets the file handle for the file that the current IsolatedStorageFileStream object encapsulates. Accessing this property is not permitted on an IsolatedStorageFileStream object, and throws an IsolatedStorageException.

IsAsync

Gets a Boolean value indicating whether the IsolatedStorageFileStream object was opened asynchronously or synchronously.

Length

Gets the length of the IsolatedStorageFileStream object.

Name

Gets the name of the FileStream that was passed to the constructor.

(Inherited from FileStream)
Position

Gets or sets the current position of the current IsolatedStorageFileStream object.

ReadTimeout

Gets or sets a value, in miliseconds, that determines how long the stream will attempt to read before timing out.

(Inherited from Stream)
SafeFileHandle

Gets a SafeFileHandle object that represents the operating system file handle for the file that the current IsolatedStorageFileStream object encapsulates.

WriteTimeout

Gets or sets a value, in miliseconds, that determines how long the stream will attempt to write before timing out.

(Inherited from Stream)

Methods

BeginRead(Byte[], Int32, Int32, AsyncCallback, Object)

Begins an asynchronous read.

BeginWrite(Byte[], Int32, Int32, AsyncCallback, Object)

Begins an asynchronous write.

Close()

Closes the current stream and releases any resources (such as sockets and file handles) associated with the current stream. Instead of calling this method, ensure that the stream is properly disposed.

(Inherited from Stream)
CopyTo(Stream)

Reads the bytes from the current stream and writes them to another stream.

(Inherited from Stream)
CopyTo(Stream, Int32)

Reads the bytes from the current stream and writes them to another stream, using a specified buffer size.

(Inherited from Stream)
CopyToAsync(Stream)

Asynchronously reads the bytes from the current stream and writes them to another stream.

(Inherited from Stream)
CopyToAsync(Stream, Int32)

Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size.

(Inherited from Stream)
CopyToAsync(Stream, Int32, CancellationToken)

Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size and cancellation token.

(Inherited from Stream)
CreateObjRef(Type)

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

(Inherited from MarshalByRefObject)
CreateWaitHandle()

Allocates a WaitHandle object.

(Inherited from Stream)
Dispose()

Releases all resources used by the Stream.

(Inherited from Stream)
Dispose(Boolean)

Releases the unmanaged resources used by the IsolatedStorageFileStream and optionally releases the managed resources.

EndRead(IAsyncResult)

Ends a pending asynchronous read request.

EndWrite(IAsyncResult)

Ends an asynchronous write.

Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
Flush()

Clears buffers for this stream and causes any buffered data to be written to the file.

Flush(Boolean)

Clears buffers for this stream and causes any buffered data to be written to the file, and also clears all intermediate file buffers.

FlushAsync()

Asynchronously clears all buffers for this stream and causes any buffered data to be written to the underlying device.

(Inherited from Stream)
FlushAsync(CancellationToken)

Asynchronously clears all buffers for this stream, causes any buffered data to be written to the underlying device, and monitors cancellation requests.

(Inherited from FileStream)
GetAccessControl()

Gets a FileSecurity object that encapsulates the access control list (ACL) entries for the file described by the current FileStream object.

(Inherited from FileStream)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetLifetimeService()

Retrieves the current lifetime service object that controls the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
InitializeLifetimeService()

Obtains a lifetime service object to control the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
Lock(Int64, Int64)

Prevents other processes from reading from or writing to the stream.

MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
MemberwiseClone(Boolean)

Creates a shallow copy of the current MarshalByRefObject object.

(Inherited from MarshalByRefObject)
ObjectInvariant()

Provides support for a Contract.

(Inherited from Stream)
Read(Byte[], Int32, Int32)

Copies bytes from the current buffered IsolatedStorageFileStream object to an array.

ReadAsync(Byte[], Int32, Int32)

Asynchronously reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.

(Inherited from Stream)
ReadAsync(Byte[], Int32, Int32, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

(Inherited from FileStream)
ReadByte()

Reads a single byte from the IsolatedStorageFileStream object in isolated storage.

Seek(Int64, SeekOrigin)

Sets the current position of this IsolatedStorageFileStream object to the specified value.

SetAccessControl(FileSecurity)

Applies access control list (ACL) entries described by a FileSecurity object to the file described by the current FileStream object.

(Inherited from FileStream)
SetLength(Int64)

Sets the length of this IsolatedStorageFileStream object to the specified value.

ToString()

Returns a string that represents the current object.

(Inherited from Object)
Unlock(Int64, Int64)

Allows other processes to access all or part of a file that was previously locked.

Write(Byte[], Int32, Int32)

Writes a block of bytes to the IsolatedStorageFileStream object using data read from a byte array.

WriteAsync(Byte[], Int32, Int32)

Asynchronously writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.

(Inherited from Stream)
WriteAsync(Byte[], Int32, Int32, CancellationToken)

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

(Inherited from FileStream)
WriteByte(Byte)

Writes a single byte to the IsolatedStorageFileStream object.

Extension Methods

GetAccessControl(FileStream)
SetAccessControl(FileStream, FileSecurity)

Applies to