How to: Read and Write to Files in Isolated Storage

To read from, or write to, a file in an isolated store, use an IsolatedStorageFileStream object with a stream reader (StreamReader object) or stream writer (StreamWriter object).

Example

The following code example obtains an isolated store and checks whether a file named TestStore.txt exists in the store. If it doesn't exist, it creates the file and writes "Hello Isolated Storage" to the file. If TestStore.txt already exists, the example code reads from the file.

using System;
using System.IO;
using System.IO.IsolatedStorage;


namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            IsolatedStorageFile isoStore = IsolatedStorageFile.GetStore(IsolatedStorageScope.User | IsolatedStorageScope.Assembly, null, null);

            if (isoStore.FileExists("TestStore.txt"))
            {
                Console.WriteLine("The file already exists!");
                using (IsolatedStorageFileStream isoStream = new IsolatedStorageFileStream("TestStore.txt", FileMode.Open, isoStore))
                {
                    using (StreamReader reader = new StreamReader(isoStream))
                    {
                        Console.WriteLine("Reading contents:");
                        Console.WriteLine(reader.ReadToEnd());
                    }
                }
            }
            else
            {
                using (IsolatedStorageFileStream isoStream = new IsolatedStorageFileStream("TestStore.txt", FileMode.CreateNew, isoStore))
                {
                    using (StreamWriter writer = new StreamWriter(isoStream))
                    {
                        writer.WriteLine("Hello Isolated Storage");
                        Console.WriteLine("You have written to the file.");
                    }
                }
            }   
        }
    }
}
Imports System.IO
Imports System.IO.IsolatedStorage

Module Module1

    Sub Main()
        Dim isoStore As IsolatedStorageFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User Or IsolatedStorageScope.Assembly, Nothing, Nothing)

        If (isoStore.FileExists("TestStore.txt")) Then
            Console.WriteLine("The file already exists!")
            Using isoStream As IsolatedStorageFileStream = New IsolatedStorageFileStream("TestStore.txt", FileMode.Open, isoStore)
                Using reader As StreamReader = New StreamReader(isoStream)
                    Console.WriteLine("Reading contents:")
                    Console.WriteLine(reader.ReadToEnd())
                End Using
            End Using
        Else
            Using isoStream As IsolatedStorageFileStream = New IsolatedStorageFileStream("TestStore.txt", FileMode.CreateNew, isoStore)
                Using writer As StreamWriter = New StreamWriter(isoStream)
                    writer.WriteLine("Hello Isolated Storage")
                    Console.WriteLine("You have written to the file.")
                End Using
            End Using
        End If 
    End Sub

End Module

See Also

IsolatedStorageFile
IsolatedStorageFileStream
System.IO.FileMode
System.IO.FileAccess
System.IO.StreamReader
System.IO.StreamWriter
File and Stream I-O
Isolated Storage