Isolated Storage in the Silverlight

Isolated Storage

Isolated Storage in the Silverlight Application

Definition:
Isolated storage is a mechanism which, provide data storage isolation and safety by defining standardized ways of associating code with saved data. Standardization provides some more benefits as well.
Uses of tools from designing, reconfiguration storage, make security
policies apart from this remove unused data all are the tasks of
Administrators

Using isolated storage there no need to write unique paths in the file system, so, hard-coded things are immaterial. With this all is controlled by computer's security policy. The uses of this is appreciable in web applications where user/client must have to use some cautions while running these applications.
Security policy doe not allow to access the file system using I/O mechanism, by default all is granted to access isolated storage

For more information on Isolated Storage Visit here

How to increase the space of the issolatedStorage of the application


Steps To Test The Current Space for the application

  1. Run any Silverlight Application Right click on it it will show you the silverlight button. Click on it

  2. Now the Silverlight properties Dialog will appear
    Now select the Application Storage Tab It will show you the Application storgae for all the silverlight application on the system

    Meetu
    Steps

  3. Create an application with the name "IsolatedStorageApp". You can name it as per your choice I will be using this in my example Application.
    Meetu

    Add New silverlight control and name it as "IncreaseIsolatedStorage.xaml"
  4. Right-click on the IsolatedStorageApp in the solution explorer

    1. Choose Add
    2. New Item

    3. Silverlight User Control. In the Name box rename it to IncreaseIsolatedStorage


  5. Meetu

  6. For our purpose we are only taking three textblocks to
    display Space Used, Space Available, Current Quota and the textbox for the New Space request. Add The Following lines in the .xaml file

    <Canvas Canvas.Left="10" Canvas.Top="10">
    <TextBlock Canvas.Left="10" x:Name="SpacedUsed" >Current Spaced Used=</TextBlock>
    <TextBlock Canvas.Left="10" x:Name="SpaceAvaiable" Canvas.Top="20">Current
    Space Available=
    </TextBlock>
    <TextBlock Canvas.Left="10" x:Name="CurrentQuota" Canvas.Top="40">Current
    Quota=
    </TextBlock>
    <TextBlock Canvas.Left="10" x:Name="NewSpace" Canvas.Top="70">New
    space (in bytes) to request=
    </TextBlock>
    <TextBox Canvas.Left="255" Canvas.Top="70" Width="100" x:Name="SpaceRequest"></TextBox>
    <TextBlock Canvas.Left="365" Canvas.Top="70" Width="60">(1048576
    = 1 MB)
    </TextBlock>
    <Button Canvas.Left="10" Content="Increase Storage" Canvas.Top="100" Width="100" Height="50" Click="Button_Click"></Button>
    <TextBlock Canvas.Left="10"
    Canvas.Top
    ="160" x:Name="Result"></TextBlock>
    </Canvas>
  7. Now our page will look like:

    Meetu


  8. To set The Values of the Three TextBlocks lets create a function GetStorageData and call it in the constructor.
    private void GetStorageData()
    {
    //creating an object for the IsolatedStorageFile
    using (IsolatedStorageFile MyAppStore = solatedStorageFile.GetUserStoreForApplication())
    {
    //calculating the space used
    SpacedUsed.Text = "Current Spaced Used = " + (MyAppStore.Quota
    - MyAppStore.AvailableFreeSpace).ToString() + " bytes";
    //getting the AvailableFreeSpace
    SpaceAvaiable.Text = "Current Space Available="
    + MyAppStore.AvailableFreeSpace.ToString() + " bytes";
    //getting the Current Quota
    CurrentQuota.Text = "Current Quota=" + MyAppStore.Quota.ToString() + " bytes";
    }
    }
    Here we will be missing a namespace "System.IO.IsolatedStorage" So include it.

  9. Now the function to increase the quota

    ///
    <summary>
    /// Increases the Isolated Storage Space of the current Application
    /// </summary>
    /// <param name="spaceRequest">
    Total Space Requested to increase
    </param>
    private void IncreaseStorage(long spaceRequest)
    {
    //creating an object for the IsolatedStorageFile for current Application
    using (IsolatedStorageFile MyAppStore = solatedStorageFile.GetUserStoreForApplication())
    {
    //Calculating the new space
    long newSpace = MyAppStore.Quota + spaceRequest;
    try
    {
    //displays a message box for the increase request.
    //if accepted by the user then displays the result as quota increased
    //else unsuccessful.
    if (true == MyAppStore.IncreaseQuotaTo(newSpace))
    {
    Result.Text = "Quota successfully increased.";
    }

else
{
Result.Text = "Quota increase was unsuccessfull.";
}
}
catch (Exception e)
{
Result.Text = "An error occured: " + e.Message;
}
//recalculate the static
GetStorageData();
}
}

Handling the button event
private
void Button_Click(object sender, RoutedEventArgs e)
{
try
{
//taking the space request in the long variable
long spaceRequest = Convert.ToInt64(SpaceRequest.Text);
//calling the function to increase the space
IncreaseStorage(spaceRequest);
}
catch
{
Result.Text = "Bad Data Entered by the user";
}
}

  1. Run the Application and click on the Button after filling the textbox with the desired space to increase.
    A Dialog box will appear for the confirmation click yes to see the results.


    Reference: http://aspnetbymeetu.blogspot.com/2009/08/isolated-storage-in-silverlight.html


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