void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
if (e.NewStartingIndex < 0)
{
goto case NotifyCollectionChangedAction.Reset;
}
for (int i = e.NewItems.Count - 1; i >= 0; i--)
{
SourceItems.Insert(e.NewStartingIndex, e.NewItems[i]);
}
break;
case NotifyCollectionChangedAction.Remove:
foreach (var item in e.OldItems)
{
SourceItems.RemoveAt(e.OldStartingIndex);
}
break;
case NotifyCollectionChangedAction.Move:
for (var i = 0; i < e.OldItems.Count; i++)
{
var oldi = e.OldStartingIndex;
var newi = e.NewStartingIndex;
if (e.NewStartingIndex < e.OldStartingIndex)
{
oldi += i;
newi += i;
}
SourceItems.Move(oldi, newi);
}
break;
case NotifyCollectionChangedAction.Replace:
case NotifyCollectionChangedAction.Reset:
default:
ReloadData();
break;
}
Device.BeginInvokeOnMainThread(() => List.UpdateLayout());
}
void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
if (e.NewStartingIndex < 0)
{
goto case NotifyCollectionChangedAction.Reset;
}
// if a NewStartingIndex that's too high is passed in just add the items.
// I realize this is enforcing bad behavior but prior to this synchronization
// code being added it wouldn't cause the app to crash whereas now it does
// so this code accounts for that in order to ensure smooth sailing for the user
if (e.NewStartingIndex >= SourceItems.Count)
{
for (int i = 0; i < e.NewItems.Count; i++)
{
SourceItems.Add((e.NewItems[i] as BindableObject).BindingContext);
}
}
else
{
for (int i = e.NewItems.Count - 1; i >= 0; i--)
{
SourceItems.Insert(e.NewStartingIndex, (e.NewItems[i] as BindableObject).BindingContext);
}
}
break;
case NotifyCollectionChangedAction.Remove:
for (int i = e.OldItems.Count - 1; i >= 0; i--)
{
SourceItems.RemoveAt(e.OldStartingIndex);
}
break;
case NotifyCollectionChangedAction.Move:
for (var i = 0; i < e.OldItems.Count; i++)
{
var oldi = e.OldStartingIndex;
var newi = e.NewStartingIndex;
if (e.NewStartingIndex < e.OldStartingIndex)
{
oldi += i;
newi += i;
}
SourceItems.Move(oldi, newi);
}
break;
case NotifyCollectionChangedAction.Replace:
case NotifyCollectionChangedAction.Reset:
default:
ClearSizeEstimate();
ReloadData();
break;
}
Device.BeginInvokeOnMainThread(() => List.UpdateLayout());
}