'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
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