Shaping ObservableCollection

Question

I have a really simple question.

I got an ObservableCollection of some ViewModel (with INotifyPropertyChanged) which gets updated frequently.

Now I need to shape the data into a new ObservableCollection of NewViewModel like this;

        var query = from o in _orders
                select new ComplexRowViewModel()
                           {Isin = o.Isin,
                            Name = o.Isin,
                            GermanSymbol = o.Exchange,
                            PrimarySymbol = o.State.ToString()};
        GridData = query;

But of course it doesn't work. Just if I use Obtics or CLINQ, the new collection gets updated if a new item comes into the first collection but if an existing item's properties change, it doesn't get updated in the new collection.

So any ideas?

score 1 · Answer 1 · edited May 23 '17 at 10:34

1

I don't know Obtics or CLINQ but it sounds like the normal behaviour of the ObservableCollection. It's not reacting on property changes of the single items it contains at all. So you have to write your own implementation of the ObservableCollection. One example is shown here: ObservableCollection that also monitors changes on the elements in collection

edited May 23 '17 at 10:34

Community

1
1

answered Jul 05 '12 at 13:35

SMB-BO

36
1

Even if I use the alternative in the link, it still doesn't work with my query. I always got a list. – Stylus Jul 05 '12 at 15:26

score 0 · Accepted Answer · answered Jul 05 '12 at 13:32

0

You should implement INotifyPropertyChange from NewViewModel too. In each of this subscibe the INotifyPropertychange on the source order and raise a new event properly.

answered Jul 05 '12 at 13:32

Felice Pollano

32,832
9
75
115

That you should implement `INotifyPropertyChanged` on the objects inside the `ObservableCollection` – Silvermind Jul 05 '12 at 17:15

Igor Buchelnikov · Answer 3 · 2019-11-21T16:22:26.410

You can also try my ObservableComputations library. Using that library:

        var query = _orders.Selecting(o => 
                new ComplexRowViewModel()
                           {Isin = o.Isin,
                            Name = o.Isin,
                            GermanSymbol = o.Exchange,
                            PrimarySymbol = o.State.ToString()};
        GridData = query;

To make code above working _orders should be of type ObservableCollection and Order class (I suggest it is type of elements in _orders ObservableCollection) should implement INotifyPropertyChanged.

Shaping ObservableCollection

3 Answers3