What event is fired when I change an element on the observable collection?

Question

I have a data grid in my view that binds to an observable collection in my view model.

When I do this:

myObservableCollection[2] = myItem;

The data grid refresh the items, and for example, if I have shorted the elements in the data grid, if myItem has updated a field that is affected by the short, is put in its new position.

However, I would like to scroll to the new position, so I am trying to use an attached behavior, that is works good when the event selection changed is fired, but I need to know what event is fired when I reasign myItem.

I have try to catch the events AddingNewItem and SourceUpdated, but neither of them is fired.

Answer 1

Netaholic gave a good part of the answer, but just to complete and put some clear visible code :

public void Demo()
{
    ObservableCollection<String> collec = new ObservableCollection<String>() {"hello"};
    collec.CollectionChanged += CollectionChanged;
    collec[0] = "goodbye";
}
void CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
    switch (e.Action)
    {
        case NotifyCollectionChangedAction.Add:
            break;
        case NotifyCollectionChangedAction.Move:
            break;
        case NotifyCollectionChangedAction.Remove:
            break;
        case NotifyCollectionChangedAction.Replace:
            Debug.WriteLine("The event you re expecting");
            break;
        case NotifyCollectionChangedAction.Reset:
            break;
        default:
            break;
    }
}

In the second parameter, you 'll find the index and object that is replaced

Regards