Handle PersistenceSaved and PersistenceLoaded Events

The PersistenceSaved and PersistenceLoaded events allow you to customize the persistence process. These events are fired only after all properties are saved or loaded.

The PersistenceSaved event handler can be used to notify the application that the save process has completed. At this point, an indicator or a message can be displayed to inform your end user that this step was performed successfully.

The PersistenceLoaded event handler can notify your end user that the loading of the control’s settings has been completed. If there are exceptions during the load process, they can be caught and reported via the PersistenceLoadedEventArgs event argument’s PropertyExceptions property. If the load process has completed successfully, a notification can be displayed.

The following example will show you how to register and use events for a PersistenceSettings object.

Add a TextBox control named 'txtAccountName' in your XAML file.

Add two buttons to execute the saving and loading process.

Add the following in your page class in code-behind:

In Visual Basic:

Dim memoryStream As New MemoryStream()
Dim settings As New PersistenceSettings()
' Counter for the saved properties
Dim SavedPropertiesCount As Integer = 0

In C#:

MemoryStream memoryStream = new MemoryStream();
PersistenceSettings settings = new PersistenceSettings();
// Counter for the saved properties
int SavedPropertiesCount = 0;

Add the following code in the page constructor after the InitializeComponent method:

In Visual Basic:

' Registers events will be raised while saving and loading persistence group
AddHandler settings.Events.SavePropertyPersistence, AddressOf Events_SavePropertyPersistence
AddHandler settings.Events.PersistenceSaved, AddressOf Events_PersistenceSaved
AddHandler settings.Events.PersistenceLoaded, AddressOf Events_PersistenceLoaded

In C#:

// Registers events will be raised while saving and loading persistence group
settings.Events.SavePropertyPersistence +=
    new EventHandler<SavePropertyPersistenceEventArgs>(Events_SavePropertyPersistence);
settings.Events.PersistenceSaved +=
    new EventHandler<PersistenceSavedEventArgs>(Events_PersistenceSaved);
settings.Events.PersistenceLoaded +=
    new EventHandler<PersistenceLoadedEventArgs>(Events_PersistenceLoaded);

Add events handlers:

In Visual Basic:

Private Sub BtnSave_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    memoryStream = PersistenceManager.Save(txtAccountName, settings)
End Sub

Private Sub Events_PersistenceSaved(ByVal sender As Object, ByVal e As PersistenceSavedEventArgs)
    ' Notification for the save process completion
    MessageBox.Show("Save process completed for " & SavedPropertiesCount.ToString() & " properties.")
End Sub

Private Sub BtnLoad_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    memoryStream.Position = 0
    PersistenceManager.Load(txtAccountName, memoryStream, settings)
End Sub

Private Sub Events_PersistenceLoaded(ByVal sender As Object, ByVal e As PersistenceLoadedEventArgs)
    Dim excCount As Integer = e.PropertyExceptions.Count
    If excCount > 0 Then
        For Each details As PropertyPersistenceExceptionDetails In e.PropertyExceptions
        MessageBox.Show(("The property " & details.PropertyInfo.Name & " has invalid value.") + details.Exception.Message.ToString())
        Next
    End If
End Sub

Private Sub Events_SavePropertyPersistence(ByVal sender As Object, ByVal e As SavePropertyPersistenceEventArgs)
    ' Count the properties being saved
    SavedPropertiesCount += 1
End Sub

In C#:

private void BtnSave_Click(object sender, RoutedEventArgs e)
{
    memoryStream = PersistenceManager.Save(txtAccountName, settings);
}

private void Events_PersistenceSaved(object sender, PersistenceSavedEventArgs e)
{
    // Notification for the save process completion
    MessageBox.Show("Save process completed for " + SavedPropertiesCount.ToString() + " properties.")
}

private void BtnLoad_Click(object sender, RoutedEventArgs e)
{
    memoryStream.Position = 0;
    PersistenceManager.Load(txtAccountName, memoryStream, settings);
}

void Events_PersistenceLoaded(object sender, PersistenceLoadedEventArgs e)
{
    int excCount = e.PropertyExceptions.Count;
    if (excCount > 0)
    {
        foreach (PropertyPersistenceExceptionDetails details in e.PropertyExceptions)
        {
            MessageBox.Show("The property " + details.PropertyInfo.Name + " has invalid value." + details.Exception.Message.ToString())
        }
    }
}

void Events_SavePropertyPersistence(object sender, SavePropertyPersistenceEventArgs e)
{
    // Count the properties being saved
    ++SavedPropertiesCount;
}

Related Topics

Persistence Settings

Exclude Specific Control Properties

Persistence Groups

Persisting Specific Control Properties

Using PropertyNamePersistenceInfo TypeConverter Property

WPF | Help Topics

Handle PersistenceSaved and PersistenceLoaded Events