我无法将DataGrid绑定到ObservableCollection

Question

I can't understand what's happening here. I have two public properties in my ViewModel:

public ObservableCollection<vw_ClientesFull> MyClients { get; set; }

private IEnumerable<vw_ClientesFull> _clients;
public IEnumerable<vw_ClientesFull> Clients
        {
            get
            {
                return _clients;
            }
            set
            {
                _clients= value;
                OnPropertyChanged("Clients");
            }
        }

Then I have a method to refresh both of them:

private void RefreshClientes()
    {
        this.serviceClient.Clientes_ListarCompleted += (s, e) =>
        {                
            Clients = e.Result;
            MyClients = new ObservableCollection<vw_ClientesFull>(Clients);
        };            
        this.serviceClient.Clientes_ListarAsync(_sRazonSocial, VendedorSel, TransporteSel, _nID, bInactivos);
    }

Them i bind my dataGrid to show the information. If I do:

ItemsSource="{Binding Path=Clients}"

If works perfect, but if i do:

ItemsSource="{Binding Path=MyClients}"

Nothing is show! Why? Doesn't ObservableCollection fire onPropertyChange Automaticaly?

Thanks for the help!!!

UPDATE

So if i need to fire the OnPropertyChange manualy, why this work without it?

public ObservableCollection<Vendedores> Vendedores { get; set; }

private void CargarVendedores()
    {        
        Vendedores = new ObservableCollection<Vendedores>(this.serviceClient.GetVendedores());                           
        this.VendedorSel = this.Vendedores.FirstOrDefault();
    }

If i bind a combobox like this:

ItemsSource="{Binding Path=Vendedores}"

Work without the OnPropertyChange! Why!

Answer 1

This problem is due to a misconception. ObservableCollection does not raise PropertyChanged, (which happens when the entire property is reassigned) when you replace it, but rather CollectionChanged (which is raised when items are added or removed). You still need to raise PropertyChanged if you plan to reassign the whole object.

Answer 2

设置MyClients的值时必须引发PropertyChanged事件，这与对Clients所做的相同。

Answer 3

Yes, ObservableCollection implements INotifyPropretyChanged. However, it isn't going to help you here :)

ObservableCollection is special because it implements INotifyCollectionChanged . In other words, it raises an event when items are added to or removed from the underlying collection. It also implements INotifyPropertyChanged, so anything bound to a property of the collection will get updated.

You are changing the variable itself though (setting to a new instance no less). This requires that the "instance" of the ObservableCollection property raise the event. In other words, you need:

private ObservableCollection<vw_ClientesFull> myClients;
public ObservableCollection<vw_ClientesFull> MyClients 
{ 
    get { return myClients; }
    set
    {
       myClients = value;
       OnPropertyChanged("MyClients"); 
}

In your update, the binding hasn't fired yet (you set in the constructor) so it gets the correct list. Subsequent changes to the list wouldn't work, however.