Comment : rendre persistantes et restaurer les propriétés de portée application d'une session d'application à l'autre

Cet exemple indique comment rendre des propriétés de portée application persistantes lorsqu'une application s'arrête, et comment restaurer des propriétés de portée application lorsqu'une application est ensuite relancée.

Exemple

L'application rend des propriétés de portée application persistantes au, et les restaure du stockage isolé. Le stockage isolé est une zone de stockage protégée qui peut être utilisée sans risque par les applications sans autorisation d'accès aux fichiers.

<Application
    xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="SDKSample.App"
    StartupUri="MainWindow.xaml" 
    Startup="App_Startup" 
    Exit="App_Exit">


...


</Application>

Imports System.IO ' StreamReader, FileMode
Imports System.IO.IsolatedStorage ' IsolatedStorageFile, IsolatedStorageFileStream

Namespace SDKSample
    Partial Public Class App
        Inherits Application
        Private filename As String = "App.txt"



...


        Private Sub App_Startup(ByVal sender As Object, ByVal e As StartupEventArgs)
            ' Restore application-scope property from isolated storage
            Dim storage As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForDomain()
            Try
                Using stream As New IsolatedStorageFileStream(filename, FileMode.Open, storage)
                Using reader As New StreamReader(stream)
                    ' Restore each application-scope property individually
                    Do While Not reader.EndOfStream
                        Dim keyValue() As String = reader.ReadLine().Split(New Char() {","c})
                        Me.Properties(keyValue(0)) = keyValue(1)
                    Loop
                End Using
                End Using
            Catch ex As FileNotFoundException
                ' Handle when file is not found in isolated storage:
                ' * When the first application session
                ' * When file has been deleted


...


            End Try
        End Sub

        Private Sub App_Exit(ByVal sender As Object, ByVal e As ExitEventArgs)
            ' Persist application-scope property to isolated storage
            Dim storage As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForDomain()
            Using stream As New IsolatedStorageFileStream(filename, FileMode.Create, storage)
            Using writer As New StreamWriter(stream)
                ' Persist each application-scope property individually
                For Each key As String In Me.Properties.Keys
                    writer.WriteLine("{0},{1}", key, Me.Properties(key))
                Next key
            End Using
            End Using
        End Sub
    End Class
End Namespace

using System.Windows; // Application, StartupEventArgs
using System.IO; // StreamReader, FileMode
using System.IO.IsolatedStorage; // IsolatedStorageFile, IsolatedStorageFileStream

namespace SDKSample
{
    public partial class App : Application
    {
        string filename = "App.txt";



...


private void App_Startup(object sender, StartupEventArgs e)
{
    // Restore application-scope property from isolated storage
    IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForDomain();
    try
    {
        using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(filename, FileMode.Open, storage))
        using (StreamReader reader = new StreamReader(stream))
        {
            // Restore each application-scope property individually
            while (!reader.EndOfStream)
            {
                string[] keyValue = reader.ReadLine().Split(new char[] {','});
                this.Properties[keyValue[0]] = keyValue[1];
            }
        }
    }
    catch (FileNotFoundException ex)
    {
        // Handle when file is not found in isolated storage:
        // * When the first application session
        // * When file has been deleted


...


            }
        }

        private void App_Exit(object sender, ExitEventArgs e)
        {
            // Persist application-scope property to isolated storage
            IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForDomain();
            using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(filename, FileMode.Create, storage))
            using (StreamWriter writer = new StreamWriter(stream))
            {
                // Persist each application-scope property individually
                foreach (string key in this.Properties.Keys)
                {
                    writer.WriteLine("{0},{1}", key, this.Properties[key]);
                }
            }
        }
    }
}