/// <summary>
/// Called when the target object is loaded.
/// <para />
/// Note that this method will only be called if the target object is a <see cref="FrameworkElement"/>.
/// </summary>
protected override void OnTargetObjectLoaded()
{
// CTL-925 Use weak events so unloaded elements (like a ComboBoxItem) can also update. The usage of
// weak events should prevent memory leaks
var listener = _onLanguageUpdatedWeakListener;
if (listener != null)
{
if (!ReferenceEquals(listener.Source, TargetObject))
{
listener.Detach();
_onLanguageUpdatedWeakListener = null;
}
if (!listener.IsSourceAlive)
{
listener.Detach();
_onLanguageUpdatedWeakListener = null;
}
}
if (_onLanguageUpdatedWeakListener is null)
{
_onLanguageUpdatedWeakListener = this.SubscribeToWeakGenericEvent <EventArgs>(_languageService, "LanguageUpdated", OnLanguageUpdated);
}
//_languageService.LanguageUpdated += OnLanguageUpdated;
}
/// <summary>
/// Unregisters the handler from the event of the given window.
/// <code>
/// protected override void RegisterEventHandler(Window window)
/// {
/// window.Closed += WindowOnClosed;
/// }
///
/// private void WindowOnClosed(object sender, EventArgs eventArgs)
/// {
/// ExecuteCommand(sender);
/// }
/// </code>
/// </summary>
/// <param name="window">The window instance the eventhandler has to be unregistered from.</param>
protected void UnregisterEventHandler(Window window)
{
if (_weakEventListener != null)
{
_weakEventListener.Detach();
_weakEventListener = null;
}
}
/// <summary>
/// Called when the source has changed.
/// </summary>
/// <param name="e">The <see cref="DependencyPropertyChangedEventArgs"/> instance containing the event data.</param>
private void OnSourceChanged(DependencyPropertyChangedEventArgs e)
{
if (e.OldValue != null)
{
switch (FocusMoment)
{
case FocusMoment.Event:
_weakEventListener?.Detach();
_weakEventListener = null;
break;
case FocusMoment.PropertyChanged:
var sourceAsPropertyChanged = e.OldValue as INotifyPropertyChanged;
if (sourceAsPropertyChanged != null)
{
sourceAsPropertyChanged.PropertyChanged -= OnSourcePropertyChanged;
}
else
{
Log.Warning("Cannot unsubscribe from previous source because it does not implement 'INotifyPropertyChanged', this should not be possible and can lead to memory leaks");
}
break;
}
}
if (e.NewValue != null)
{
switch (FocusMoment)
{
case FocusMoment.Event:
if (string.IsNullOrEmpty(EventName))
{
throw new InvalidOperationException("Property 'EventName' is required when FocusMode is 'FocusMode.Event'");
}
_weakEventListener = this.SubscribeToWeakEvent(Source, EventName, OnSourceEventOccurred);
break;
case FocusMoment.PropertyChanged:
if (string.IsNullOrEmpty(PropertyName))
{
throw new InvalidOperationException("Property 'PropertyName' is required when FocusMode is 'FocusMode.PropertyChanged'");
}
var sourceAsPropertyChanged = e.NewValue as INotifyPropertyChanged;
if (sourceAsPropertyChanged is null)
{
throw new InvalidOperationException("Source does not implement interface 'INotifyfPropertyChanged', either implement it or change the 'FocusMode'");
}
sourceAsPropertyChanged.PropertyChanged += OnSourcePropertyChanged;
break;
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="WindowLogic"/> class.
/// </summary>
/// <param name="targetWindow">The window this provider should take care of.</param>
/// <param name="viewModelType">Type of the view model.</param>
/// <param name="viewModel">The view model to inject.</param>
/// <exception cref="ArgumentNullException">The <paramref name="targetWindow"/> is <c>null</c>.</exception>
public WindowLogic(IView targetWindow, Type viewModelType = null, IViewModel viewModel = null)
: base(targetWindow, viewModelType, viewModel)
{
var targetWindowType = targetWindow.GetType();
var closedEvent = targetWindowType.GetEventEx("Closed");
var eventName = closedEvent != null ? "Closed" : "Unloaded";
_targetWindowClosedWeakEventListener = this.SubscribeToWeakGenericEvent <EventArgs>(targetWindow, eventName, OnTargetWindowClosed);
_targetWindowClosedEventName = eventName;
Log.Debug("Using '{0}.{1}' event to determine window closing", targetWindowType.FullName, eventName);
}
/// <summary>
/// Registers the handler to the event of the given window.
/// <code>
/// protected override void RegisterEventHandler(Window window)
/// {
/// window.Closing += WindowOnClosing;
/// }
///
/// private void WindowOnClosing(object sender, CancelEventArgs cancelEventArgs)
/// {
/// ExecuteCommand(sender);
/// }
/// </code>
/// </summary>
/// <param name="window">The window instance the eventhandler has to be registered to.</param>
protected void RegisterEventHandler(Window window)
{
_weakEventListener = this.SubscribeToWeakEvent(window, EventName, (Action)OnEventOccurred);
}