/// <summary>
/// Removes all views that are not longer part of the ItemSource to avoid duplicated views.
/// </summary>
void DisposeOldElements()
{
List <Xamarin.Forms.View> removableItems;
if (ItemSource == null)
{
//Remove all items if the new ItemSource is empty.
removableItems = ContentGrid.Children.ToList();
Debug.WriteLine("Remove all items from gallerie.");
}
else
{
//Only remove items that are no longer part of the new ItemSource
removableItems = ContentGrid.Children.Where(o => !ItemSource.Contains(o.BindingContext)).ToList();
}
//Remove items and dispose the handler
while (removableItems.Any())
{
var view = removableItems.First();
((TapGestureRecognizer)view.GestureRecognizers[0]).Tapped -= GestureRekognizerOnTapped;
ContentGrid.Children.Remove(view);
removableItems.RemoveAt(0);
}
}