protected override void OnAttach()
{
Region.ActiveViews.CollectionChanged +=
(sender, args) =>
{
if (args.Action == NotifyCollectionChangedAction.Add)
{
foreach (var newView in args.NewItems)
{
var dependentViews = new List <DependentViewInfo>();
if (_dependentViewsCache.ContainsKey(newView))
{
dependentViews = _dependentViewsCache[newView];
}
else
{
var attributes = newView.GetType().GetCustomAttributes <DependentViewAttribute>();
foreach (var attribute in attributes)
{
var dependentViewInfo = new DependentViewInfo(attribute.Region, _container.Resolve(attribute.Type));
dependentViews.Add(dependentViewInfo);
//внедрение в зависимый вид контекста основного вида
if (attribute.HasSameDataContext)
{
if (newView is FrameworkElement mainView && dependentViewInfo.View is FrameworkElement dependentView)
{
dependentView.DataContext = mainView.DataContext;
}
}
}
_dependentViewsCache.Add(newView, dependentViews);
}
dependentViews.ForEach(x => Region.RegionManager.Regions[x.Region].Add(x.View));
}
}
else if (args.Action == NotifyCollectionChangedAction.Remove)
{
foreach (var oldView in args.OldItems)
{
if (_dependentViewsCache.ContainsKey(oldView))
{
var dependentViews = _dependentViewsCache[oldView];
dependentViews.ForEach(x => Region.RegionManager.Regions[x.Region].Remove(x.View));
//если вид нужно удалить
if (!ShouldKeepAlive(oldView))
{
_dependentViewsCache.Remove(oldView);
}
}
}
}
};
}
private DependentViewInfo GetDependentView(DependentViewAttribute attribute)
{
var info = new DependentViewInfo
{
TargetRegionName = attribute.TargetRegionName,
View = attribute.ViewType != null?_containerProvider.Resolve(attribute.ViewType) : null
};
return(info);
}
