IsolatedStorageFileStream 类

定义

命名空间:

System.IO.IsolatedStorage

程序集:

System.IO.IsolatedStorage.dll

Source:

IsolatedStorageFileStream.cs

公开独立存储中的文件。

public ref class IsolatedStorageFileStream : System::IO::FileStream

public class IsolatedStorageFileStream : System.IO.FileStream

type IsolatedStorageFileStream = class
    inherit FileStream

Public Class IsolatedStorageFileStream
Inherits FileStream

继承

Object

MarshalByRefObject

Stream

FileStream

IsolatedStorageFileStream

示例

以下控制台应用程序演示如何使用 IsolatedStorageFile 和 IsolatedStorageFileStream 将数据写入独立存储文件。 请求用户登录。 如果用户是新用户，则会在独立存储中将新闻 URL 和体育 URL 记录为个人首选项。 如果用户是返回的用户，则会显示用户的当前首选项。 在此命名空间中使用的代码示例显示在此示例应用程序的上下文中。 可以使用 Storeadm.exe（独立存储工具） 实用工具列出和删除使用此控制台应用程序创建的隔离存储文件。

// 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;

[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();
    }
}

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.IO
Imports System.IO.IsolatedStorage
Imports System.Security.Policy
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


        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
    End Class
    _

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

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

        ' 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

        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
End Namespace 'ISOCS

注解

使用此类在独立存储中读取、写入和创建文件。

由于此类扩展了 FileStream，因此，在大多数情况下，可以使用 IsolatedStorageFileStream 实例，否则可以使用 FileStream，例如构造 StreamReader 或 StreamWriter。

此类型实现 IDisposable 接口。 使用完该类型后，应直接或间接释放它。 若要直接释放类型，请在 try/catch 块中调用其 Dispose 方法。 若要间接处理它，请使用语言构造（如 using（在 C# 中）或 Using（在 Visual Basic 中）。 有关详细信息，请参阅 IDisposable 接口主题中的“使用实现 IDisposable 的对象”部分。

重要

独立存储不适用于 Windows 8.x 应用商店应用。 请改用 Windows 运行时 API 中包含的 Windows.Storage 命名空间中的应用程序数据类来存储本地数据和文件。 有关详细信息，请参阅 Windows 开发人员中心中的 应用程序数据。

构造函数

IsolatedStorageFileStream(String, FileMode)	初始化一个 IsolatedStorageFileStream 对象的新实例，该实例授予对指定 mode中 path 指定的文件的访问权限。
IsolatedStorageFileStream(String, FileMode, FileAccess)	使用所请求的 access 类型初始化 IsolatedStorageFileStream 类的新实例，以访问指定 mode中指定的 path指定的文件。
IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare)	使用 share指定的文件共享模式，使用指定的文件 access初始化 IsolatedStorageFileStream 类的新实例，以访问由 path指定的文件 mode指定的文件。
IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare, Int32)	使用由 share指定的文件共享模式（指定 buffersize 指定）初始化 IsolatedStorageFileStream 类的新实例，以 path指定 mode指定的文件 access访问由 path指定的文件。
IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare, Int32, IsolatedStorageFile)	使用指定的文件 modeaccess、share指定的文件共享模式、指定的 buffersize 以及 isf指定的 IsolatedStorageFile 上下文，初始化 IsolatedStorageFileStream 类的新实例，以 path指定的文件访问指定的文件。
IsolatedStorageFileStream(String, FileMode, FileAccess, FileShare, IsolatedStorageFile)	使用 share指定的文件共享模式以及由 isf指定的 IsolatedStorageFile 上下文中，使用 mode指定的文件 access初始化 IsolatedStorageFileStream 类的新实例，以访问由 path指定的文件。
IsolatedStorageFileStream(String, FileMode, FileAccess, IsolatedStorageFile)	使用指定的文件 access以及由 isf指定的 IsolatedStorageFile 上下文初始化 IsolatedStorageFileStream 类的新实例，以访问由指定 mode中指定的 path 指定的文件。
IsolatedStorageFileStream(String, FileMode, IsolatedStorageFile)	初始化 IsolatedStorageFileStream 类的新实例，以访问由 path指定的文件，在指定的 mode，以及由 isf指定的 IsolatedStorageFile 上下文中。

属性

CanRead	获取一个布尔值，该值指示是否可以读取文件。
CanSeek	获取一个布尔值，该值指示是否支持查找操作。
CanTimeout	获取一个值，该值确定当前流是否可以超时。 (继承自 Stream)
CanWrite	获取一个布尔值，该值指示是否可以写入文件。
Handle	已过时. 获取当前 IsolatedStorageFileStream 对象封装的文件的文件句柄。 不允许在 IsolatedStorageFileStream 对象上访问此属性，并引发 IsolatedStorageException。
IsAsync	获取一个布尔值，该值指示 IsolatedStorageFileStream 对象是异步打开还是同步打开。
Length	获取 IsolatedStorageFileStream 对象的长度。
Name	获取在 FileStream中打开的文件的绝对路径。 (继承自 FileStream)
Position	获取或设置当前 IsolatedStorageFileStream 对象的当前位置。
ReadTimeout	获取或设置一个值（以毫秒为单位），该值确定流在超时前尝试读取的时间。 (继承自 Stream)
SafeFileHandle	获取一个 SafeFileHandle 对象，该对象表示当前 IsolatedStorageFileStream 对象封装的文件的操作系统文件句柄。
WriteTimeout	获取或设置一个值（以毫秒为单位），该值确定流在超时之前尝试写入的时间。 (继承自 Stream)

方法

BeginRead(Byte[], Int32, Int32, AsyncCallback, Object)	开始异步读取。
BeginWrite(Byte[], Int32, Int32, AsyncCallback, Object)	开始异步写入。
Close()	关闭当前流并释放与当前流关联的任何资源（如套接字和文件句柄）。 (继承自 FileStream)
CopyTo(Stream)	从当前流中读取字节并将其写入另一个流。 这两个流位置都是按复制的字节数进行高级的。 (继承自 Stream)
CopyTo(Stream, Int32)	公开独立存储中的文件。 (继承自 FileStream)
CopyToAsync(Stream)	从当前流异步读取字节并将其写入另一个流。 这两个流位置都是按复制的字节数进行高级的。 (继承自 Stream)
CopyToAsync(Stream, CancellationToken)	使用指定的取消标记异步读取当前流中的字节并将其写入另一个流。 这两个流位置都是按复制的字节数进行高级的。 (继承自 Stream)
CopyToAsync(Stream, Int32)	使用指定的缓冲区大小异步读取当前流中的字节并将其写入另一个流。 这两个流位置都是按复制的字节数进行高级的。 (继承自 Stream)
CopyToAsync(Stream, Int32, CancellationToken)	使用指定的缓冲区大小和取消令牌异步读取当前文件流中的字节，并将其写入另一个流。 (继承自 FileStream)
CreateObjRef(Type)	创建一个对象，其中包含生成用于与远程对象通信的代理所需的所有相关信息。 (继承自 MarshalByRefObject)
CreateWaitHandle()	已过时. 分配 WaitHandle 对象。 (继承自 Stream)
Dispose()	释放 Stream使用的所有资源。 (继承自 Stream)
Dispose(Boolean)	释放 IsolatedStorageFileStream 使用的非托管资源，并选择性地释放托管资源。
DisposeAsync()	异步释放 IsolatedStorageFileStream使用的非托管资源。
EndRead(IAsyncResult)	结束挂起的异步读取请求。
EndWrite(IAsyncResult)	结束异步写入。
Equals(Object)	确定指定的对象是否等于当前对象。 (继承自 Object)
Flush()	清除此流的缓冲区，并导致任何缓冲数据写入文件。
Flush(Boolean)	清除此流的缓冲区，并导致任何缓冲数据写入文件，并清除所有中间文件缓冲区。
FlushAsync()	异步清除此流的所有缓冲区，并导致任何缓冲数据写入基础设备。 (继承自 Stream)
FlushAsync(CancellationToken)	异步清除此流的缓冲区，并导致任何缓冲数据写入文件。
GetAccessControl()	获取一个 FileSecurity 对象，该对象封装当前 FileStream 对象描述的文件的访问控制列表（ACL）条目。 (继承自 FileStream)
GetHashCode()	用作默认哈希函数。 (继承自 Object)
GetLifetimeService()	已过时. 检索控制此实例的生存期策略的当前生存期服务对象。 (继承自 MarshalByRefObject)
GetType()	获取当前实例的 Type。 (继承自 Object)
InitializeLifetimeService()	已过时. 获取生存期服务对象来控制此实例的生存期策略。 (继承自 MarshalByRefObject)
Lock(Int64, Int64)	防止其他进程读取或写入流。
MemberwiseClone()	创建当前 Object的浅表副本。 (继承自 Object)
MemberwiseClone(Boolean)	创建当前 MarshalByRefObject 对象的浅表副本。 (继承自 MarshalByRefObject)
ObjectInvariant()	已过时. 为 Contract提供支持。 (继承自 Stream)
Read(Byte[], Int32, Int32)	将当前缓冲 IsolatedStorageFileStream 对象的字节复制到字节数组。
Read(Span<Byte>)	将当前缓冲 IsolatedStorageFileStream 对象的字节复制到字节范围。
ReadAsync(Byte[], Int32, Int32)	从当前流异步读取字节序列，并通过读取的字节数推进流中的位置。 (继承自 Stream)
ReadAsync(Byte[], Int32, Int32, CancellationToken)	将字节从当前缓冲 IsolatedStorageFileStream 对象异步复制到字节数组。
ReadAsync(Memory<Byte>, CancellationToken)	将字节从当前缓冲 IsolatedStorageFileStream 对象异步复制到字节内存范围。
ReadAtLeast(Span<Byte>, Int32, Boolean)	至少从当前流中读取最小字节数，并通过读取的字节数提升流中的位置。 (继承自 Stream)
ReadAtLeastAsync(Memory<Byte>, Int32, Boolean, CancellationToken)	异步读取当前流的最小字节数，按读取的字节数推进流中的位置，并监视取消请求。 (继承自 Stream)
ReadByte()	从隔离存储中的 IsolatedStorageFileStream 对象读取单个字节。
ReadExactly(Byte[], Int32, Int32)	从当前流中读取 count 字节数，并提升流中的位置。 (继承自 Stream)
ReadExactly(Span<Byte>)	从当前流中读取字节，并在填充 buffer 之前推进流中的位置。 (继承自 Stream)
ReadExactlyAsync(Byte[], Int32, Int32, CancellationToken)	从当前流异步读取 count 字节数，推进流中的位置，并监视取消请求。 (继承自 Stream)
ReadExactlyAsync(Memory<Byte>, CancellationToken)	从当前流异步读取字节，在填充 buffer 之前先行流中的位置，并监视取消请求。 (继承自 Stream)
Seek(Int64, SeekOrigin)	将此 IsolatedStorageFileStream 对象的当前位置设置为指定值。
SetAccessControl(FileSecurity)	将 FileSecurity 对象描述的访问控制列表（ACL）条目应用于当前 FileStream 对象描述的文件。 (继承自 FileStream)
SetLength(Int64)	将此 IsolatedStorageFileStream 对象的长度设置为指定的 value。
ToString()	返回一个表示当前对象的字符串。 (继承自 Object)
Unlock(Int64, Int64)	允许其他进程访问以前锁定的文件的所有或部分。
Write(Byte[], Int32, Int32)	使用从包含字节数组的缓冲区读取的数据，将字节块写入隔离存储文件流对象。
Write(ReadOnlySpan<Byte>)	使用从包含只读字节范围的缓冲区读取的数据，将字节块写入隔离存储文件流对象。
WriteAsync(Byte[], Int32, Int32)	以异步方式将字节序列写入当前流，并通过写入的字节数推进此流中的当前位置。 (继承自 Stream)
WriteAsync(Byte[], Int32, Int32, CancellationToken)	使用从包含字节数组的缓冲区读取的数据，以异步方式将字节块写入隔离存储文件流对象。
WriteAsync(ReadOnlyMemory<Byte>, CancellationToken)	使用从包含只读字节内存范围的缓冲区读取的数据，以异步方式将字节块写入隔离存储文件流对象。
WriteByte(Byte)	将单个字节写入 IsolatedStorageFileStream 对象。

扩展方法

GetAccessControl(FileStream)	返回文件的安全信息。
SetAccessControl(FileStream, FileSecurity)	更改现有文件的安全属性。
CopyToAsync(Stream, PipeWriter, CancellationToken)	使用取消令牌从 Stream 异步读取字节并将其写入指定的 PipeWriter。
ConfigureAwait(IAsyncDisposable, Boolean)	配置如何执行从异步可释放项返回的任务的 await。