private void HandleItemSelection(ItemClickEventArgs args)
{
if (SelectionMode != ListViewSelectionMode.None)
{
var newSelection = ListViewAdapter.GetItemAt(args.Position);
switch (SelectionMode)
{
case ListViewSelectionMode.Single:
var selectedItem = ListViewAdapter.SelectedItems.FirstOrDefault();
// Unselect the current item only if a new selection is made or
// the option to unselect the current item is activated.
if (selectedItem != null && (selectedItem != newSelection || UnselectOnClick))
{
ListViewAdapter.SetItemSelection(selectedItem, null, false);
}
if (selectedItem != newSelection)
{
ListViewAdapter.SetItemSelection(
newSelection,
(args.View as ItemContainerHolder)?.Child as SelectorItem,
true
);
}
SelectedItem = newSelection;
if (selectedItem != newSelection)
{
SelectionChanged?.Invoke(this, new SelectionChangedEventArgs(this, new[] { selectedItem }, new[] { newSelection }));
}
break;
case ListViewSelectionMode.Multiple:
ListViewAdapter.SetItemSelection(
ListViewAdapter.GetItemAt(args.Position),
args.View as SelectorItem,
!ListViewAdapter.SelectedItems.Contains(newSelection)
);
break;
}
SelectedItems = ListViewAdapter.SelectedItems.ToArray();
}
}
private void UpdateSelection(IList <object> newSelection)
{
if (ListViewAdapter != null)
{
if (!ListViewAdapter.SelectedItems.SequenceEqual(newSelection))
{
var removed = ListViewAdapter
.SelectedItems
.Except(newSelection)
.ToArray();
var added = newSelection
.Except(ListViewAdapter.SelectedItems)
.ToArray();
removed.ForEach((object i) => ListViewAdapter.SetItemSelection(i, null, false));
added.ForEach((object i) => ListViewAdapter.SetItemSelection(i, null, true));
SelectionChanged?.Invoke(this, new SelectionChangedEventArgs(this, removed, added));
}
}
}
partial void OnLoadedPartial()
{
SetupItemClickListener();
if (_adapter != null)
{
// The adapter has already been initialized.
// Re-initializing the adapter would cause the ListView to lose its state (i.e., scroll position) after a reload.
return;
}
_adapter = new ListViewAdapter();
_adapter.ItemContainerStyle = ItemContainerStyle;
_adapter.ItemContainerFactory = () => new ListViewItem()
{
ShouldHandlePressed = false
};
_adapter.ItemTemplate = ItemTemplate;
_adapter.ItemTemplateSelector = ItemTemplateSelector;
_adapter.ItemClickCommand = _itemClickCommand;
_adapter.Header = Header;
_adapter.Footer = Footer;
_adapter.HeaderTemplate = HeaderTemplate;
_adapter.FooterTemplate = FooterTemplate;
_adapter.ItemsSource = ItemsSource;
_adapter.CustomViewTypeCount = this.CustomViewTypeCount;
_adapter.GroupStyle = this.GroupStyle;
_adapter.ItemContainerHolderStretchOrientation = Windows.UI.Xaml.Controls.Orientation.Horizontal;
_adapter.SecondaryPool = _secondaryPool;
SelectedItems.Safe()
.ForEach((object i) => _adapter.SetItemSelection(i, null, true));
Adapter = _adapter;
IsResetScrollOnItemsSourceChanged = true;
}