IsolatedStorageFileStream 类
公开独立存储中的文件。
**命名空间:**System.IO.IsolatedStorage
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
<ComVisibleAttribute(True)> _
Public Class IsolatedStorageFileStream
Inherits FileStream
用法
Dim instance As IsolatedStorageFileStream
[ComVisibleAttribute(true)]
public class IsolatedStorageFileStream : FileStream
[ComVisibleAttribute(true)]
public ref class IsolatedStorageFileStream : public FileStream
/** @attribute ComVisibleAttribute(true) */
public class IsolatedStorageFileStream extends FileStream
ComVisibleAttribute(true)
public class IsolatedStorageFileStream extends FileStream
备注
使用该类在独立存储中读取、写入和创建文件。
由于该类扩展 FileStream，因此在可能使用 FileStream 的大多数情况下（例如，构造 StreamReader 或 StreamWriter）都可以使用 IsolatedStorageFileStream 的实例。
示例
下面的控制台应用程序演示了如何使用 IsolatedStorageFile 和 IsolatedStorageFileStream 将数据写入到独立存储文件。系统要求用户登录。如果用户是新用户，则“新闻 URL”和“体育 URL”将作为个人首选项记录在独立存储中。如果用户是老用户，则显示该用户的当前首选项。在此命名空间中使用的代码示例出现在此示例应用程序的上下文中。可以使用 独立存储工具 (Storeadm.exe) 实用工具列出和移除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.
Imports System
Imports System.IO
Imports System.IO.IsolatedStorage
Imports System.Security.Policy
Imports Microsoft.VisualBasic
Imports Microsoft.Win32.SafeHandles
Imports System.Security.Permissions
Namespace ISOCS
_
Class ConsoleApp
<STAThread()> _
Overloads Shared Sub Main(ByVal args() As String)
' Prompt the user for their username.
Console.WriteLine("Enter your login ID:")
' Does no error checking.
Dim lp As New LoginPrefs(Console.ReadLine())
If lp.NewPrefs Then
Console.WriteLine("Please set preferences for a new user.")
GatherInfoFromUser(lp)
' Write the new preferences to storage.
Dim percentUsed As Double = lp.SetPrefsForUser()
Console.WriteLine(("Your preferences have been written. Current space used is " & percentUsed.ToString() & " %"))
Else
Console.WriteLine("Welcome back.")
Console.WriteLine("Your preferences have expired, please reset them.")
GatherInfoFromUser(lp)
lp.SetNewPrefsForUser()
Console.WriteLine("Your news site has been set to {0}" & ControlChars.Cr & " and your sports site has been set to {1}.", lp.NewsUrl, lp.SportsUrl)
End If
lp.GetIsoStoreInfo()
Console.WriteLine("Enter 'd' to delete the IsolatedStorage files and exit, or press any other key to exit without deleting files.")
Dim consoleInput As String = Console.ReadLine()
If consoleInput.ToLower() = "d" Then
lp.DeleteFiles()
lp.DeleteDirectories()
End If
End Sub 'Main
Shared Sub GatherInfoFromUser(ByVal lp As LoginPrefs)
Console.WriteLine("Please enter the URL of your news site.")
lp.NewsUrl = Console.ReadLine()
Console.WriteLine("Please enter the URL of your sports site.")
lp.SportsUrl = Console.ReadLine()
End Sub 'GatherInfoFromUser
End Class 'ConsoleApp
_
<SecurityPermissionAttribute(SecurityAction.Demand, Flags:=SecurityPermissionFlag.UnmanagedCode)> _
Public Class LoginPrefs
Public Sub New(ByVal myUserName As String)
userName = myUserName
myNewPrefs = GetPrefsForUser()
End Sub 'New
Private userName As String
Private myNewsUrl As String
Public Property NewsUrl() As String
Get
Return myNewsUrl
End Get
Set(ByVal Value As String)
myNewsUrl = Value
End Set
End Property
Private mySportsUrl As String
Public Property SportsUrl() As String
Get
Return mySportsUrl
End Get
Set(ByVal Value As String)
mySportsUrl = Value
End Set
End Property
Private myNewPrefs As Boolean
Public ReadOnly Property NewPrefs() As Boolean
Get
Return myNewPrefs
End Get
End Property
Private Function GetPrefsForUser() As Boolean
Try
' Retrieve an IsolatedStorageFile for the current Domain and Assembly.
Dim isoFile As IsolatedStorageFile = _
IsolatedStorageFile.GetStore(IsolatedStorageScope.User _
Or IsolatedStorageScope.Assembly _
Or IsolatedStorageScope.Domain, Nothing, Nothing)
Dim isoStream As New IsolatedStorageFileStream(Me.userName, FileMode.Open, _
FileAccess.Read, FileShare.Read)
' farThe code executes to this point only if a file corresponding to the username exists.
' Though you can perform operations on the stream, you cannot get a handle to the file.
Try
Dim aFileHandle As SafeFileHandle = isoStream.SafeFileHandle
Console.WriteLine(("A pointer to a file handle has been obtained. " & aFileHandle.ToString() & " " & aFileHandle.GetHashCode()))
Catch ex As Exception
' Handle the exception.
Console.WriteLine("Expected exception")
Console.WriteLine(ex.ToString())
End Try
Dim reader As New StreamReader(isoStream)
' Read the data.
Me.NewsUrl = reader.ReadLine()
Me.SportsUrl = reader.ReadLine()
reader.Close()
isoFile.Close()
Return False
Catch ex As System.IO.FileNotFoundException
' Expected exception if a file cannot be found. This indicates that we have a new user.
Return True
End Try
End Function 'GetPrefsForUser
Public Function GetIsoStoreInfo() As Boolean
Try
'Get a User store with type evidence for the current Domain and the Assembly.
Dim isoFile As IsolatedStorageFile = _
IsolatedStorageFile.GetStore(IsolatedStorageScope.User Or _
IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, _
GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))
Dim dirNames As String() = isoFile.GetDirectoryNames("*")
Dim fileNames As String() = isoFile.GetFileNames("*")
Dim name As String
' List directories currently in this Isolated Storage.
If dirNames.Length > 0 Then
For Each name In dirNames
Console.WriteLine("Directory Name: " & name)
Next name
End If
' List the files currently in this Isolated Storage.
' The list represents all users who have personal preferences stored for this application.
If fileNames.Length > 0 Then
For Each name In fileNames
Console.WriteLine("File Name: " & name)
Next name
End If
isoFile.Close()
Return True
Catch ex As Exception
Console.WriteLine(ex.ToString())
End Try
End Function 'GetIsoStoreInfo
Public Function SetPrefsForUser() As Double
Try
Dim isoFile As IsolatedStorageFile
isoFile = IsolatedStorageFile.GetUserStoreForDomain()
' Open or create a writable file.
Dim isoStream As New IsolatedStorageFileStream(Me.userName, FileMode.OpenOrCreate, _
FileAccess.Write, isoFile)
Dim writer As New StreamWriter(isoStream)
writer.WriteLine(Me.NewsUrl)
writer.WriteLine(Me.SportsUrl)
' Calculate the amount of space used to record the user's preferences.
Dim d As Double = Convert.ToDouble(isoFile.CurrentSize) / Convert.ToDouble(isoFile.MaximumSize)
Console.WriteLine(("CurrentSize = " & isoFile.CurrentSize.ToString()))
Console.WriteLine(("MaximumSize = " & isoFile.MaximumSize.ToString()))
' StreamWriter.Close implicitly closes isoStream.
writer.Close()
isoFile.Dispose()
isoFile.Close()
Return d
Catch ex As Exception
' Add code here to handle the exception.
Console.WriteLine(ex)
Return 0.0
End Try
End Function 'SetPrefsForUser
Public Sub DeleteFiles()
Try
Dim isoFile As IsolatedStorageFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User Or IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))
Dim name As String
Dim dirNames As String() = isoFile.GetDirectoryNames("*")
Dim fileNames As String() = isoFile.GetFileNames("*")
' List the files currently in this Isolated Storage.
' The list represents all users who have personal
' preferences stored for this application.
If fileNames.Length > 0 Then
For Each name In fileNames
' Delete the files.
isoFile.DeleteFile(name)
Next name
'Confirm no files are left.
fileNames = isoFile.GetFileNames("*")
End If
Catch ex As Exception
Console.WriteLine(ex.ToString())
End Try
End Sub 'DeleteFiles
' This method deletes directories in the specified Isolated Storage, after first
' deleting the files they contain. In this example, the Archive directory is deleted.
' There should be no other directories in this Isolated Storage.
Public Sub DeleteDirectories()
Try
Dim isoFile As IsolatedStorageFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User _
Or IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, _
GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))
Dim name As String
Dim dirNames As String() = isoFile.GetDirectoryNames("*")
Dim fileNames As String() = isoFile.GetFileNames("Archive\*")
' Delete all the files currently in the Archive directory.
If fileNames.Length > 0 Then
For Each name In fileNames
isoFile.DeleteFile(("Archive\" & name))
Next name
'Confirm no files are left.
fileNames = isoFile.GetFileNames("Archive\*")
End If
If dirNames.Length > 0 Then
For Each name In dirNames
' Delete the Archive directory.
isoFile.DeleteDirectory(name)
Next name
End If
dirNames = isoFile.GetDirectoryNames("*")
isoFile.Remove()
Catch ex As Exception
Console.WriteLine(ex.ToString())
End Try
End Sub 'DeleteDirectories
Public Function SetNewPrefsForUser() As Double
Try
Dim inputChar As Byte
Dim isoFile As IsolatedStorageFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User Or IsolatedStorageScope.Assembly Or IsolatedStorageScope.Domain, GetType(System.Security.Policy.Url), GetType(System.Security.Policy.Url))
' If this is not a new user, archive the old preferences and
' overwrite them using the new preferences.
If Not Me.myNewPrefs Then
If isoFile.GetDirectoryNames("Archive").Length = 0 Then
isoFile.CreateDirectory("Archive")
Else
Dim source As New IsolatedStorageFileStream(Me.userName, FileMode.OpenOrCreate, isoFile)
Dim canWrite, canRead As Boolean
' This is the stream from which data will be read.
If source.CanRead Then canRead = True Else canRead = False
Console.WriteLine("Is the source file readable? " & canRead)
Console.WriteLine("Creating new IsolatedStorageFileStream for Archive.")
' Open or create a writable file.
Dim target As New IsolatedStorageFileStream("Archive\ " & Me.userName, _
FileMode.OpenOrCreate, FileAccess.Write, FileShare.Write, isoFile)
' This is the stream to which data will be written.
If target.CanWrite Then canWrite = True Else canWrite = False
Console.WriteLine("Is the target file writable? " & canWrite)
target.SetLength(0) 'rewind the target file
' Stream the old file to a new file in the Archive directory.
If source.IsAsync And target.IsAsync Then
' IsolatedStorageFileStreams cannot be asynchronous. However, you
' can use the asynchronous BeginRead and BeginWrite functions
' with some possible performance penalty.
Console.WriteLine("IsolatedStorageFileStreams cannot be asynchronous.")
Else
Console.WriteLine("Writing data to the new file.")
While source.Position < source.Length
inputChar = CByte(source.ReadByte())
target.WriteByte(inputChar)
End While
' Determine the size of the IsolatedStorageFileStream
' by checking its Length property.
Console.WriteLine(("Total Bytes Read: " & source.Length))
End If
' After you have read and written to the streams, close them.
target.Close()
source.Close()
End If
End If
' Open or create a writable file with a maximum size of 10K.
Dim isoStream As New IsolatedStorageFileStream(Me.userName, FileMode.OpenOrCreate, _
FileAccess.Write, FileShare.Write, 10240, isoFile)
isoStream.SetLength(0) 'Position to overwrite the old data.
Dim writer As New StreamWriter(isoStream)
' Update the data based on the new inputs.
writer.WriteLine(Me.NewsUrl)
writer.WriteLine(Me.SportsUrl)
' Calculate the amount of space used to record this user's preferences.
Dim d As Double = Convert.ToDouble(isoFile.CurrentSize) / Convert.ToDouble(isoFile.MaximumSize)
Console.WriteLine(("CurrentSize = " & isoFile.CurrentSize.ToString()))
Console.WriteLine(("MaximumSize = " & isoFile.MaximumSize.ToString()))
' StreamWriter.Close implicitly closes isoStream.
writer.Close()
isoFile.Close()
Return d
Catch ex As Exception
Console.WriteLine(ex.ToString())
Return 0.0
End Try
End Function 'SetNewPrefsForUser
End Class 'LoginPrefs
End Namespace 'ISOCS
// This sample demonstrates methods of classes found in the System.IO IsolatedStorage namespace.
using System;
using System.IO;
using System.IO.IsolatedStorage;
using System.Security.Policy;
using Microsoft.Win32.SafeHandles;
using System.Security.Permissions;
[assembly: CLSCompliantAttribute(true)]
class ConsoleApp
{
[STAThread]
static void Main(string[] args)
{
// Prompt the user for their username.
Console.WriteLine("Login:");
// Does no error checking.
LoginPrefs lp = new LoginPrefs(Console.ReadLine());
if (lp.NewPrefs)
{
Console.WriteLine("Please set preferences for a new user.");
GatherInfoFromUser(lp);
// Write the new preferences to storage.
double percentUsed = lp.SetPrefsForUser();
Console.WriteLine("Your preferences have been written. Current space used is " + percentUsed.ToString() + " %");
}
else
{
Console.WriteLine("Welcome back.");
Console.WriteLine("Your preferences have expired, please reset them.");
GatherInfoFromUser(lp);
lp.SetNewPrefsForUser();
Console.WriteLine("Your news site has been set to {0}\n and your sports site has been set to {1}.", lp.NewsUrl, lp.SportsUrl);
}
lp.GetIsoStoreInfo();
Console.WriteLine("Enter 'd' to delete the IsolatedStorage files and exit, or press any other key to exit without deleting files.");
string consoleInput = Console.ReadLine();
if (consoleInput.ToLower() == "d")
{
lp.DeleteFiles();
lp.DeleteDirectories();
}
}
static void GatherInfoFromUser(LoginPrefs lp)
{
Console.WriteLine("Please enter the URL of your news site.");
lp.NewsUrl = Console.ReadLine();
Console.WriteLine("Please enter the URL of your sports site.");
lp.SportsUrl = Console.ReadLine();
}
}
[SecurityPermissionAttribute(SecurityAction.Demand, Flags=SecurityPermissionFlag.UnmanagedCode)]
public class LoginPrefs
{
public LoginPrefs(string myUserName)
{
userName = myUserName;
myNewPrefs = GetPrefsForUser();
}
string userName;
string myNewsUrl;
public string NewsUrl
{
get { return myNewsUrl; }
set { myNewsUrl = value; }
}
string mySportsUrl;
public string SportsUrl
{
get { return mySportsUrl; }
set { mySportsUrl = value; }
}
bool myNewPrefs;
public bool NewPrefs
{
get { return myNewPrefs; }
}
private bool GetPrefsForUser()
{
try
{
// Retrieve an IsolatedStorageFile for the current Domain and Assembly.
IsolatedStorageFile isoFile =
IsolatedStorageFile.GetStore(IsolatedStorageScope.User |
IsolatedStorageScope.Assembly |
IsolatedStorageScope.Domain,
null,
null);
IsolatedStorageFileStream isoStream =
new IsolatedStorageFileStream(this.userName,
FileMode.Open,
FileAccess.Read,
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.
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();
}
}
继承层次结构
System.Object
System.MarshalByRefObject
System.IO.Stream
System.IO.FileStream
System.IO.IsolatedStorage.IsolatedStorageFileStream
线程安全
此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。
平台
Windows 98、Windows 2000 SP4、Windows Millennium Edition、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0