كيفية القيام بما يلي: استمرار واستعادة خصائص نطاق التطبيق عبر جلسات عمل التطبيق
يوضح هذا المثال كيف تستمر خصائص نطاق التطبيق عند إيقاف تشغيل أحد التطبيقات وكيفية استعادة خصائص نطاق التطبيق عند تشغيل التطبيق مرة أخرى.
مثال
يحتفظ التطبيق بخصائص نطاق التطبيق فى التخزين المعلوم ويسترجعها منها كذلك. التخزين المعزول هى مساحة تخزين محمية يمكن استخدامها بأمان بواسطة التطبيقات دون أخذ أذونات وصول للملف.
<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]);
}
}
}
}
}