diff options
Diffstat (limited to 'Xamarin.Forms.Core')
| -rw-r--r-- | Xamarin.Forms.Core/ItemsViewSimple.cs | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/Xamarin.Forms.Core/ItemsViewSimple.cs b/Xamarin.Forms.Core/ItemsViewSimple.cs index fd631838..34b77264 100644 --- a/Xamarin.Forms.Core/ItemsViewSimple.cs +++ b/Xamarin.Forms.Core/ItemsViewSimple.cs @@ -73,7 +73,7 @@ namespace Xamarin.Forms var dynamicItemSource = _itemSource as INotifyCollectionChanged; if (dynamicItemSource != null) { - new WeakNotifyCollectionChanged(dynamicItemSource, OnCollectionChange); + new WeakNotifyCollectionChanged(this, dynamicItemSource); } } @@ -82,34 +82,37 @@ namespace Xamarin.Forms internal event NotifyCollectionChangedEventHandler CollectionChanged; - void OnCollectionChange(object sender, NotifyCollectionChangedEventArgs e) + internal void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) { CollectionChanged?.Invoke(sender, e); } sealed class WeakNotifyCollectionChanged { - readonly INotifyCollectionChanged _source; - // prevent the itemSource from keeping the itemsView alive - readonly WeakReference<NotifyCollectionChangedEventHandler> _weakTarget; + readonly WeakReference<INotifyCollectionChanged> _weakCollection; + readonly WeakReference<ItemsView> _weakSource; - public WeakNotifyCollectionChanged(INotifyCollectionChanged source, NotifyCollectionChangedEventHandler target) + public WeakNotifyCollectionChanged(ItemsView source, INotifyCollectionChanged incc) { - _weakTarget = new WeakReference<NotifyCollectionChangedEventHandler>(target); - _source = source; - _source.CollectionChanged += OnCollectionChanged; + incc.CollectionChanged += OnCollectionChanged; + + _weakSource = new WeakReference<ItemsView>(source); + _weakCollection = new WeakReference<INotifyCollectionChanged>(incc); } - public void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) + void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) { - NotifyCollectionChangedEventHandler weakTarget; - if (!_weakTarget.TryGetTarget(out weakTarget)) + ItemsView source; + if (!_weakSource.TryGetTarget(out source)) { - _source.CollectionChanged -= OnCollectionChanged; + INotifyCollectionChanged collection; + if (_weakCollection.TryGetTarget(out collection)) + collection.CollectionChanged -= OnCollectionChanged; + return; } - weakTarget(sender, e); + source.OnCollectionChanged(sender, e); } } |