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Hi Greg,
Your right. In the mean time we've cooked up a solution. Below's (part of) our code. We attach to the ListChanged event and act accordingly. This class is base on a class we call the ObservableList<T> which already has an implementation of the OnListChanged event (override). The class uses the RelatedEntityList<T> of DevForce and maintains its own list (that's why there is a RefillList()). The class is build using the principal: 'First make it work, than make it better and than make it fast'. We've proved it works.
Regards,
Paul Sinnema
Diartis AG
public override void OnListChanged(object sender, ObservableListChangedEventArgs e)
{
if (m_SuspendItemChangedEvents == 0)
{
switch (e.Action)
{
case ObservableListChangedAction.Add:
base.OnListChanged(sender, e);
AttachPropertyChangedEvents(e.NewItems);
break;
case ObservableListChangedAction.Remove:
DetachPropertyChangedEvents(e.OldItems);
base.OnListChanged(sender, e);
break;
case ObservableListChangedAction.Replace:
case ObservableListChangedAction.Move:
DetachPropertyChangedEvents(e.OldItems);
base.OnListChanged(sender, e);
AttachPropertyChangedEvents(e.NewItems);
break;
case ObservableListChangedAction.None:
case ObservableListChangedAction.Reset:
case ObservableListChangedAction.Resync:
base.OnListChanged(sender, e);
break;
default:
throw new InvalidArgumentException("e.Action", e.Action);
}
}
}
private void AttachChangedEvents()
{
if (m_RelatedEntityList != null)
{
m_RelatedEntityList.CollectionChanged += RelatedEntityListCollectionChanged;
AttachPropertyChangedEvents(m_RelatedEntityList);
}
}
private void AttachPropertyChangedEvents(IList list)
{
foreach (T item in list)
{
item.PropertyChanged += ItemPropertyChanged;
}
}
private void DetachChangedEvents()
{
if (m_RelatedEntityList != null)
{
m_RelatedEntityList.CollectionChanged -= RelatedEntityListCollectionChanged;
DetachPropertyChangedEvents(m_RelatedEntityList);
}
}
private void DetachPropertyChangedEvents(IList list)
{
foreach (T item in list)
{
item.PropertyChanged -= ItemPropertyChanged;
}
}
private void ItemPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (sender is T)
{
int index = IndexOf((T)sender);
if (index >= 0)
{
this.OnItemChanged(sender, new ItemPropertyChangedEventArgs(this, sender, index, e.PropertyName));
}
RefillList();
}
}
-------------
Senior Developer at Diartis AG in Switzerland.
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