private void SourceSelection_CollectionChanged([NotNull] object sender, [NotNull] NotifyCollectionChangedEventArgs e)
{
if (IsUpdating)
{
return;
}
IsUpdating = true;
try
{
_selector.CommitEdit();
var selectedItems = _selector.GetSelectedItems();
var itemsToSelect = e.NewItems;
var itemsToDeselect = e.OldItems;
switch (e.Action)
{
case NotifyCollectionChangedAction.Reset:
var sourceSelection = (IList)sender;
_selector.SynchronizeWithSource(sourceSelection);
break;
case NotifyCollectionChangedAction.Add:
if ((selectedItems.Count == 0) && (itemsToSelect.Count == 1))
{
_selector.SelectSingleItem(itemsToSelect);
}
else
{
_selector.AddItemsToSelection(itemsToSelect);
}
break;
case NotifyCollectionChangedAction.Remove:
selectedItems.RemoveRange(itemsToDeselect);
break;
case NotifyCollectionChangedAction.Replace:
if ((selectedItems.Count == 1) && (itemsToSelect.Count == 1))
{
_selector.SelectSingleItem(itemsToSelect);
}
else
{
selectedItems.RemoveRange(itemsToDeselect);
_selector.AddItemsToSelection(itemsToSelect);
}
break;
}
}
finally
{
IsUpdating = false;
}
}
private static void SynchronizeWithSource([NotNull] this Selector selector, [NotNull, ItemCanBeNull] IList sourceSelection)
{
Contract.Requires(selector != null);
Contract.Requires(sourceSelection != null);
var selectedItems = selector.GetSelectedItems();
if ((selectedItems.Count == sourceSelection.Count) && sourceSelection.All(selectedItems.Contains))
{
return;
}
selector.CommitEdit();
// Clear the selection.
selector.SelectedIndex = -1;
if (sourceSelection.Count == 1)
{
selector.SelectSingleItem(sourceSelection);
}
else
{
selector.AddItemsToSelection(sourceSelection);
}
}
private static void SynchronizeWithSource(this Selector selector, IList sourceSelection)
{
var selectedItems = selector.GetSelectedItems();
if ((selectedItems.Count == sourceSelection.Count) && sourceSelection.Cast <object>().All(selectedItems.Contains))
{
return;
}
selector.CommitEdit();
// Clear the selection.
selector.SelectedIndex = -1;
if (sourceSelection.Count == 1)
{
selector.SelectSingleItem(sourceSelection);
}
else
{
selector.AddItemsToSelection(sourceSelection);
}
}
