IsolatedStorageFileStream 类

定义

public ref class IsolatedStorageFileStream : System::IO::Stream

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

public class IsolatedStorageFileStream : System.IO.Stream

public class IsolatedStorageFileStream : System.IO.FileStream

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

type IsolatedStorageFileStream = class
    inherit Stream

type IsolatedStorageFileStream = class
    inherit FileStream

[<System.Runtime.InteropServices.ComVisible(true)>]
type IsolatedStorageFileStream = class
    inherit FileStream

Public Class IsolatedStorageFileStream
Inherits Stream

Public Class IsolatedStorageFileStream
Inherits FileStream

继承

Object

Stream

IsolatedStorageFileStream

继承

Object

MarshalByRefObject

Stream

FileStream

IsolatedStorageFileStream

属性

ComVisibleAttribute

示例

以下控制台应用程序演示了如何使用 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，新闻 URL 和体育 URL 将作为个人首选项记录在独立存储中。 如果用户是返回的用户，则会显示用户的当前首选项。 此示例应用程序的上下文中提供了整个命名空间中使用的代码示例。 可以使用 Storeadm.exe (独立存储工具) 实用工具列出并删除使用此控制台应用程序创建的独立存储文件。

// 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 FileStream了 ，因此大多数情况下可以使用 的 IsolatedStorageFileStream 实例，例如 FileStream 构造 StreamReader 或 StreamWriter。

此类型实现 IDisposable 接口。 在使用完类型后，您应直接或间接释放类型。 若要直接释放类型，请在 try/catch 块中调用其 Dispose 方法。 若要间接释放类型，请使用 using（在 C# 中）或 Using（在 Visual Basic 中）等语言构造。 有关详细信息，请参阅 IDisposable 接口主题中的“使用实现 IDisposable 的对象”一节。

构造函数

属性

方法

显式接口实现

扩展方法

适用于