protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e)
{
if (e.NewItems == e.OldItems)
{
return;
}
if (e.Action == NotifyCollectionChangedAction.Reset)
{
this.Items.Clear();
}
if (e.NewItems != null)
{
foreach (object item in e.NewItems)
{
Dispatcher.BeginInvoke(DispatcherPriority.Loaded, (Action)(() =>
{
TabItem tab = (this.ItemContainerGenerator.ContainerFromItem(item) as TabItem);
var tabVM = tab.DataContext;
TabExpTabItemBaseVM tabExp = item as TabExpTabItemBaseVM;
if (tabExp == null || tabExp.Expandible)
{
if (!this.TabsList.Contains(tab))
{
tab.Tag = tabVM;
this.TabsList.Add(tab);
}
ToggleButton tog = tab.FindFirstVisualChildOfType <ToggleButton>();
if (!this.TogsList.Contains(tog))
{
this.TogsList.Add(tog);
tog.Click += ToggleButtonClick;
}
}
else
{
Border bd = tab.Template.FindName("Bd", tab) as Border;
ContentControl cc = new ContentControl();
cc.Name = "Content";
cc.Content = tabExp.TEHeaderTemplate;
cc.Template = tabExp.TEHeaderTemplate;
bd.Child = cc;
}
}));
}
}
if (e.OldItems != null)
{
foreach (object item in e.OldItems)
{
//If the DataContext is not saved in other place, the reference is lost BEFORE this event launches and the
//click event of the togglebutton can't ever be unsubscribed(ContainerFromItem don't work, NOTHING work, e.OldItems
//have NO reference to the tabitem when it reaches this event), so all tabitems are saved in a list field
//and each datacontext saved as each tabitem's tag (OnApplyTemplate and OnItemsChanged if(e.NewItems != null) ),
//so the tag and the tabitem persist, can be found in this event, and togglebutton click can be unsubscribed
TabItem tab = this.TabsList.Find(x => x.Tag == item);
//If the tab is not expandible, it have no tog button and no event, so don't unsubscribe
if (tab != null)
{
ToggleButton tog = tab.FindFirstVisualChildOfType <ToggleButton>();
tog.Click -= ToggleButtonClick;
this.TogsList.Remove(tog);
}
this.TabsList.Remove(tab);
}
}
base.OnItemsChanged(e);
}