public ObservableGroupCollection(IGroupingCollection <K, T> item, Func <K, K, bool> equalityComparer)
{
_equalityComparer = equalityComparer;
if (item != null)
{
foreach (T t in item)
{
SetupPropertyChanged(t, equalityComparer);
}
}
}
void SetupPropertyChanged(T propChangeItem, Func <K, K, bool> equalityComparer)
{
propChangeItem.PropertyChanged += (sender, e) => {
if (e.PropertyName == "SortingKey")
{
//using (BlockReentrancy())
{
T changedItem = (T)sender;
IGroupingCollection <K, T> oldGroup = null, newGroup = null;
foreach (var group in Items) //go through all groups to find item
{
if (oldGroup == null /* || newGroup == null*/)
{
foreach (var item2 in group)
{
if (oldGroup == null && item2 == changedItem)
{
oldGroup = group;
}
}
}
if (newGroup == null && equalityComparer(group.Key, changedItem.SortingKey))
{
newGroup = group;
}
}
if (oldGroup != null)
{
oldGroup.Remove(changedItem);
if (oldGroup.Count == 0)
{
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, oldGroup));
Items.Remove(oldGroup);
}
}
#if DEBUG
else
{
throw new Exception("oldGroup == null");
}
#endif
if (newGroup == null)
{
Items.Add(newGroup = new Grouping <K, T> (changedItem.SortingKey, changedItem));
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, newGroup));
}
else
{
foreach (var item in newGroup)
{
if (item == changedItem)
{
return;
}
}
newGroup.Add(changedItem);
}
}
}
};
}
