public void OpenScreen <TScreen>(IScreenFactory <TScreen> factory)
where TScreen : class, IScreenBase
{
ScreenCreationBehavior creationBehavior = GetCreationBehavior(factory);
IScreenBase alreadyOpenScreen = null;
switch (creationBehavior)
{
case ScreenCreationBehavior.MultipleInstances:
break;
case ScreenCreationBehavior.SingleInstance:
alreadyOpenScreen = _screens
.SingleOrDefault(x => x.GetType() == factory.ScreenType);
break;
case ScreenCreationBehavior.UseScreenLocation:
alreadyOpenScreen = Screens
.FirstOrDefault(x => factory.CreatesScreensEquivalentTo(x));
break;
}
bool wasAlreadyOpen = alreadyOpenScreen != null;
IScreenBase s;
if (wasAlreadyOpen)
{
s = alreadyOpenScreen;
}
else
{
// If the constructor or Initialize handler of the screen throws an
// exception we exit here and 'ActiveScreen' is not changed. The screen
// itself makes sure that is consistently closed in case of an exception.
s = _screens.AddScreen(factory);
s.Children
.Add(new ScreenCloseHandler(requestClose => CloseScreen(s, requestClose)));
}
// Activate does handle exceptions correctly and rethrows them, so we skip
// the publishing of the 'ScreenOpenedEvent'.
ActiveScreen = s;
_eventAggregator.Publish(
ScreenOpenedEvent,
new ScreenOpenedEventArgs(this, s, wasAlreadyOpen)
);
}
public ScreenCreationBehaviorAttribute(ScreenCreationBehavior creationBehavior)
{
CreationBehavior = creationBehavior;
}