private void ChildVMCollection_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (SynchDisabled)
{
return;
}
SynchDisabled = true;
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
foreach (object item in e.NewItems)
{
var mItem = (ChildVM)item;
int idx = ChildMCollection.IndexOf(mItem);
// the operation could have been either Insert or Add
if (0 <= idx && idx <= ChildVMCollection.Count - 1)
{
ChildMCollection.Insert(idx, mItem);
}
else
{
ChildMCollection.Add(mItem);
}
}
break;
case NotifyCollectionChangedAction.Remove:
foreach (object item in e.OldItems)
{
var vmItem = item as ChildVM;
// find VM objects that wrap the relevant model object and remove them
IEnumerable <ChildM> query;
while ((query = from vm in ChildMCollection
where vm.Text == vmItem.Text
select vm).Count() > 0)
{
ChildM mItem = query.First();
int index = ChildMCollection.IndexOf(vmItem);
ChildMCollection.Remove(vmItem); // TODO: what if I implement the == or != operator?
}
}
break;
case NotifyCollectionChangedAction.Reset:
ChildMCollection.Clear();
break;
case NotifyCollectionChangedAction.Move:
// TODO: handle multiple items
ChildMCollection.Move(e.OldStartingIndex, e.NewStartingIndex);
break;
case NotifyCollectionChangedAction.Replace:
// TODO: handle multiple items
ChildMCollection[e.OldStartingIndex] = (ChildM)e.NewItems[0];
break;
default:
throw new NotImplementedException();
}
SynchDisabled = false;
}
public ChildVM(ChildM m)
{
Text = m.Text;
}