protected override NotifyCollectionChangedEventArgs BuildCompositeEventArgs(IReadOnlyObservableList <T> sender, NotifyCollectionChangedEventArgs e)
{
int GetSenderStartIndex() => ObservableCollections.TakeWhile(x => x != sender).Sum(x => x.Count);
int GetNewItemsIndex() => GetSenderStartIndex() + (e.NewStartingIndex >= 0 ? e.NewStartingIndex : throw new InvalidOperationException());
int GetOldItemsIndex() => GetSenderStartIndex() + (e.OldStartingIndex >= 0 ? e.OldStartingIndex : throw new InvalidOperationException());
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
{
return(CollectionChangedEventArgs.InsertRange(e.NewItems, GetNewItemsIndex()));
}
case NotifyCollectionChangedAction.Remove:
{
return(CollectionChangedEventArgs.RemoveRange(e.OldItems, GetOldItemsIndex()));
}
case NotifyCollectionChangedAction.Replace:
{
return(CollectionChangedEventArgs.ReplaceRange(e.OldItems, e.NewItems, GetOldItemsIndex()));
}
case NotifyCollectionChangedAction.Move:
{
return(CollectionChangedEventArgs.MoveRange(e.OldItems, GetOldItemsIndex(), GetNewItemsIndex()));
}
case NotifyCollectionChangedAction.Reset:
{
if (sender.Count == Count)
{
return(CollectionChangedEventArgs.Clear());
}
return(CollectionChangedEventArgs.RemoveRange(sender.ToList(), GetSenderStartIndex()));
}
default:
throw new NotSupportedException();
}
}
public MyMessage(ObservableCollections col1, ObservableCollections col2, ObservableCollections col3)
{
this.Col1 = col1;
this.Col2 = col2;
this.Col3 = col3;
}